I think it's related to aesthetics, but I think when it's interpersonal, it takes on a dimension that's not there for a painting or a sunset. Humans are built for relationships and there is that pull towards one another that's not sexual, or at least has a dimension that's not sexual.
I think, when we're talking about sexual orientation, we're talking about a tendency to find appealing; as one person described it to me, in the first instance it's what you notice, even without intending to look.
Ok, I think it is a good way to phrase the part I am speaking of, the "initial notice, that you do not intend."
I think sexual orientation is something else, we can discuss after working through the dynamics of attraction/temptation. Sexual orientation is by definition broader than the specific sub-set of people that, as you described it earlier, push buttons for an individual.
However, that initial notice that you do not intend then prompts some kind of processing.
Do I look more with the intent of lusting?
Do I "bounce the eyes" as one author put it, so as to not see the person further?
Do I admit the attraction and move on, having decided not to give it any traction, as it would be wrong?
Do I physically flee the area?
I have seen all the above listed as things people do, and there could be more. But at the point it hits that decision I would say it is already a temptation, whether strong or weak. If it were not then no decision would be necessary. You would just go on as normal.
I am thinking of the Latin; id quod volo (that which I desire); but that is the same verb for what I will. (So in the old Latin marriage rite, "Will you..." was responded to with "volo," "I will." That is, not a future tense, but a present tense I will to do it. It's at the root of English words such as volunteer and voluntary, arising from the free exercise of one's will. It's that range of words which is informing the way I think about the difference between attraction, desire, choice and so on.
So, in that semantic field, what I will or choose to do is the same as what I desire to do. When you speak of "desire," I read that as "what I choose, or would choose to do if I could." Not, "what might appeal to me but I would not choose." That latter sense is closer to what I mean by attraction but not desire.
Ok, then we are using slightly different understandings, which might be part of the problem coming to terms. I think desire can reference will, but also I think sometimes it is speaking of sinful propensities, more than will or decision. The flesh has propensities for how it wants to act that are against the Spirit. For now I will avoid the term "desire" in this conversation, and try to look at other terms.
I would include "what might appeal to me but I would not choose" as within the idea of temptation, depending on why I would not choose it. If it is referring to something I have chosen before, and the reason I am not choosing it now is I realize how poorly that went and I now have Christ working in me NOT to choose it, then it is still temptation. Even if it is lightly felt it is temptation, or I wouldn't be thinking it through in the first place because it wouldn't register as an issue to address.
In other words, if something is attractive enough that I know it could be a problem, then that is in itself a temptation. Something is before me I have to take a course of action regarding, because it is attractive and forbidden, and therefore dangerous.