There have been a number of philosophers in the Platonic tradition who have attended to sadness and the whole order of emotions in terms of proper pleasure and pain. You can find the latter in Aristotle, and more explicitly in Augustine's idea that there is an ideal order of love (ordo amoris), proper things we should feel delight or sadness in. In the modern era, one of the more fascinating philosophers to think systematically about values in the Platonic tradition (but he is no commentator on Plato, he is working out a novel ethic) is Max Scheler (1874-1928). You might find his book Formalism in Ethics and the Non-Formal Ethics of Value fascinating.
Great question that gets to the heart of a current debate! If you have a very narrow concept of logic (in which logic only refers to the laws of identity, non-contradiction, and the law of excluded middle) and if your notion of observation is again narrow perhaps only allowing in empirical data then perhaps it is neither logical nor illogical to mourn the death of someone. BUT, you may have a broader concept of observation. For example, in your question you refer to "a loved one." Can one observe the fact that a person is worthy of love or should be loved? I personally think one can. In that case, it would be quite logical (you would be acting with consistency) for you to act in a way that is appropriate when one's beloved one dies. On this expanded front, imagine you truly love Skippy and desire her or his happiness; that is, you believe it would be good for Skippy to be happy and bad if Skippy were to die before fulfilling the desires of his or her heart. Then, surely, it appears you should mourn Skippy's death. Matters may turn out otherwise, however, if you deeply restrict concepts like love, logic, and observation. I suggest the more open approach is the better one in that it captures more fully the way in which our experience is saturated with values that call for our response. You might check out Parfit's extraordinary two volume work On What Matters for a look at the issues and why there is some dispute today among philosophers on the fact/value distinction.
Emotion is very important in all human activities, philosophy included. Many arguments are fashioned as they are not in a disinterested desire to attain the truth but to get promoted, impress a potential partner, do down an enemy and so on. These might be regarded as cynical comments but then philosophers are usually human beings and they will then have human emotions.
One does sometimes just not like a theory and then we look for reasons of a logical kind to disprove it. It could be something about it that raises our suspicions, like someone we dislike propounding it, for example. One thing I have noted is that few philosophers like to admit they have changed their minds on an issue, we normally stick to our guns throughout our careers. After all, consistency is supposed to be a logical virtue.
if you're asking 'can some people rise above jealousy?', surely the answer is yes -- i can't help but think, though, that this question is more in the domain of psychology than philosophy .... (unless you believe that a proper theory of the world could help here -- eg Buddhism, which teaches you to free yourself from all attachments -- I suppose THAT would help with jealousy! --) ... For something you might enjoy reading on the subject, have a look at Proust's Remembrance of Things Past -- it's the second or third book, which is the story of Swann's jealousy over a woman named Odette ....
Because you take a position to be something one can act on, I interpret this in the sense of "commitment" or "disposition". So suppose a person has the deliberate disposition to "fix" student grades whenever he is offered $100 or more to do so. (This might be a professor or an administrator or a person with access to the university's computer system.) Surely this is an unethical disposition, that is, a disposition that one ought not to have, and the person so disposed is typically unethical on account of this disposition even if he never engages in any unethical conduct (e.g., because he is never offered a sufficiently large amount).
It's different with emotions because these cannot be simply willed away. It is problematic, then, to characterize a person as unethical on account of an emotion that she just finds herself having, without choice. Still, we do have ways of influencing our future emotions, and there are surely emotions that we ought to try to diminish or eradicate (e.g. disgust for people of certain skin color or sexual orientation, which can be overcome by seeking friendships with some such people). And one can then say in a temporally more extended sense that certain emotions and those who have the are unethical: in cases where one could and ought to have rid oneself of them.
Still, the basic response is the same for positions and emotions. There are three different entities up for moral assessment here. First, there are the positions and emotions themselves, which were the subject of your query. Whether they are unethical is entirely unaffected by whether the person who has them acts on them or not. Second, there are the actions motivated by the position or emotion. These are typically unethical; but if the person having the position or emotion in question never acts on it, then there are no actions to assess. Third, there are the persons themselves. Consider two persons who, otherwise equal, are disposed to fix grades for bribes of $100 or more (as described above), with one of them receiving and accepting several offers while the other receives none. Should we say that the former is more unethical than the latter because he had the "bad" luck of being offered sufficiently large bribes? This is the position Bernard Williams takes (in Moral Luck) and it is also the position implicit in the law (if the assassin's bullet is miraculously stopped by the intended victim's cell phone, then the assassin will receive the lesser punishment for attempted murder). On the other side, Immanuel Kant holds that luck can make no difference: that persons should be morally judged by their dispositions alone. Thus, the person less reluctant to be bribed is (other things equal) the more unethical person even if his counterpart accepts many bribes while he himself (for lack of opportunity) never accepts a single one.
There seem to be forms of hedonistic utilitarianism (maximize pleasure) that might allow for the permissibility of unethical opinions, provided they are not likely to lead to acts of great disutility and the one who has such opinions enjoys holding them. That, in any case, was once advanced as an objection to J.J.C. Smart's brand of utilitarianism. But I suggest it is difficult to insure that unethical opinions don't impact our action. Someone who thinks illegal immigrants should be shot may not do any shooting, but he or she might injure or harm an immigrant, given the chance. Also, ethics (in the west and east) is often (though not always) cast in terms of love and hate one is to love justice, hate cruelty. Someone with the unethical opinions you describe --wanting to shoot illegal immigrants rather than merely prevent them entering one's country seems to be someone who is loving cruelty. And I think many of us do think that cruel desires and pleasures are ethically repulsive in themselves. In the course of some research yesterday, I came across on the web Himmler's speech in the early 1940s about the importance (and duty) of the SS killing all Jews. It is absolutely horrifying. Now imagine a person NEVER acts in any anti-simitic way, but he listens with pleasure over and over again to Himmler and sympathizes with the SS (imagine, in his opinion, never acted on, this person wishes the Nazis has succeeded). I think most of us would see this as a profound flaw or deep sin.
Just one other thought: I have replied without making any appeal to religious ethics (though I suppose the concept of "sin" is in the neighborhood of religion). But for many Jews, Christians, Muslims, Hindus, Buddhists, and others, one's interior life (beliefs and desires) are of profound ethical and religious significance, and not just one's external behavior.
You say that love is an emotion, and in some sense we can grant that. But saying it suggests that love is a feeling, and that, in turn, suggests that it's like a warm sensation in one's tummy -- something that we can simply detect by introspection and that we can't (or can't easily) be wrong about. But it's more complicated than that. If I love someone, I can still have moments when I feel angry at them, for example. But my momentary anger -- a non-loving feeling -- isn't the same as not loving them. Love is, among other things, a complicated set of dispositions. Some of them are dispositions to feel a certain way in certain situations, and others are dispositions to behave in certain ways. I might be momentarily angry with my daughter, for example, but it might be true that if anything were to happen to her, I would be beside myself with grief. I might also be willing to make considerable sacrifices for her well-being. I might worry about her, take time to check up on her, and do all of this not just out of some sense of duty. Those dispositions are much better indicators of my love for her than my momentary feeling of anger.
On the other hand, if I wouldn't grieve the loss of my daughter, wouldn't go out of my way to help her, didn't care whether I spent time with her and so on, the fact that I would say I love her wouldn't count for much. Indeed, the fact that I believed I loved her might best be seen as a kind of self-deception due, perhaps, to my wanting to think well of myself. Similar comments apply to romantic love, of course.
Because love is a lot more than a feeling, people are quite capable of being wrong about whether they love someone. They can tell themselves that they don't love someone when they really do (think of someone who swears they no longer love their ex-lover when it's obvious to everyone else that they do), and they can tell themselves that they do love someone when they really don't. The connection with behavior is clear. If love involves dispositions to feel and to act, then the actions someone actually performs can be signs of their real dispositions.
Of course, this is only a small part of the story. The notion of love is both complicated and not entirely precise. It's certainly possible to love someone and yet not to be the jealous type. It's certainly possible to love someone and not be willing to go along with all of their wishes or principles; the examples you cite seem pretty clearly to be compatible with really loving someone. But if A treats B with reliable cruelty, for example, it would take a very complicated story to make sense of A's claim to really love B. This is so even if A really believes that s/he loves B.
The more general point is this: there are some things about our minds that we know better than others do. But there's a good deal about our minds that we can't discover just by introspection. We can be quite wrong about our selves in various ways. Add to that the fact that our psychologies have such an important role in producing our behavior, and it's not hard to see why sometimes others are in a better position than we are to make judgements about our own psychologies. The case of love is just one among many.
There are two ways to read your questions:
1. Would we be better off never feeling negative emotions because they were never called for--i.e., because we never experienced the sorts of events that make grief or anger an appropriate reaction? Or...
2. Would we be better off never feeling negative emotions regardless of what happens to us?
I am inclined to answer 'no' to the second question. While some (e.g., Stoics and Buddhists, at least on an oversimplified reading) suggest that we should approach negative events with a level of detachment that make grief, anger, or despair inappropriate, and the wise or enlightened person will reach a point where she can avoid feeling such emotions, I find that approach inappropriate. I think it would be both mistaken and almost inhuman not to feel grief at the death of one's child or not to feel some level of anger at the terrorists who perpetrated 9/11 (whether despair is ever appropriate is trickier). So, I do not think we would be better off if we could get ourselves to stop feeling these emotions no matter what happens to us. There's another question here, which is whether we could have been built such that the appropriate response to tragic events was not negative emotions, but if that were the case, I'm more inclined to say we would not really be human anymore (notice the Stoic or Buddhist is not built so as to never feel these emotions; he has to develop that attitude).
The first interpretation of your question suggests the debate about the problem of evil and suffering. It seems like an all-good, all-powerful God could have made this world a 'heaven on earth' such that we could be built the way we are but we simply did not face any (or many) tragic events. Then we could be human and still avoid any (or as much) despair, grief, anger, and suffering. Wouldn't that be the best of all possible worlds? Well, answers vary here. Some think tragic events and our appropriate emotional responses to them are necessary for us to become better people, build virtues like courage, and learn to empathize (of course, without tragedy, the need for courage and empathy is minimized). When I teach the problem of evil, I like to point out that without tragedies and the negative emotions that go with them, we'd certainly have less interesting literature and movies. But I have to say, I don't think this whimsical point nor the 'soul-building' defense are strong enough to explain why an all-good God would allow so much suffering (especially so much suffering of innocent children).
Here's a riddle your question raises too: If God exists and is entirely perfect, does he (can he) feel any negative emotions, such as grief and anger? If so, how? If not, then it would suggest we'd be more perfect if we were less human and more godly.
Your question is an interesting one. It's puzzling at first to imagine experiencing two very different, apparently conflicting momentary feelings at the same time. For example: it's hard to know what we would make of someone who claimed to be experiencing a feeling of great calm and extreme anxiety both at the same time. I say "hard" advisedly, however, rather than "impossible." Feeling-states can be quite complicated, and although we can't experience literally contradictory states at the same time (because contradictions can't be true), it might well take near-paradoxical language to convey what some feeling states are like.
In any case, something like this is almost certainly part of the story. We're clearly capable of experiencing complex combinations of feeling tone. For example: you've probably had the experience of really enjoying a conversation while at the same time being aware that you have a mild but unpleasant backache. One might be foreground, so to speak, and the other background. That's probably no more or less odd than feeling frustrated that one's work is going badly and yet being able to keep in awareness a sense that overall things are going well.
There's a related but somewhat different way to come at the problem. The word "happiness" is sometimes used to mean a certain specific feeling, but that's not the only way to think of it. We can also think of happiness as a more general, less momentary state -- in something like the way you suggest yourself. Life may be going well overall. You may be appropriately challenged, have strong relationships, be invested in your work and your projects, but still be able to experience passing ups and downs. There is no mystery in saying that one is leading a happy life or that overall things are going well, and yet that one is sad today because a friend experienced a setback, for instance. On the contrary, if happiness includes emotional health, then this possibility is inevitable.
So two approaches here. One is the one you allude to: feeling states can be complicated, and can sometimes contain parts, so to speak, with different valences. But the other is to distinguish between the momentary feeling of happiness and the larger, more stable state of well-being. The second can be quite real -- and one can know that it's quite real -- even in moments where the first is absent. Indeed, that sounds a lot like part of the flow of a normal life.
If one means by 'emotional infidelity' feeling attracted to another person than the one to whom is committed, or to feeling enmity or having bad thoughts towards someone towards to whom one is committed in friendship, than the phenomenon seems very possible indeed. Consider the following case, which I think is not idiosyncratic: something bad happens to a friend, and instead of sympathizing with that person--at least in one's thoughts--one takes pleasure in that friend's misfortune. (In German, this is called 'Schadenfreude'.) In taking pleasure in the misfortune of a friend, one is being emotionally unfaithful to that friendship--which, I think, in principle requires in principle that one sympathize and commiserate with the misfortunes of one's friend. The deep question, however, is why, if cases such as these are indeed correctly characterized as cases of emotional infidelity, why such emotional infidelity is as common as I think it is: one explanation, deriving from Christianity, is that human beings are Fallen, or, to put it in terms that Kant employs in Religion Within the Limits of Mere Reason, that human beings are 'radically evil'. Regardless of whether the Fall is actual historical event--as certain Christians are inclined to think--I myself am inclined to think that there is something deeply correct about this explanation, and that human beings may well, in virtue of being fundamentally self-absorbed and self-interested, always liable to violate the demands of friendship and love, even if only in thought and not in deed. (Perhaps this is too gloomy a view of human nature; nevertheless introspection and the observation of others seem, sadly, to lend it considerable evidential support.)