I have two possibly conflicting views of love: one is binary, the other is scalar. I recognize a continuum of degree of affection for cat and my friends, relatives and acquaintences, all of which could be lumped under love. But as I wrote quixoticfish at one point, love is the sort of thing where you know it when you see it. If you don't know, it isn't love.
So I visualize a spectrum with a border at one end, beyond which I would point and say "there, that's love". Sort of like the line of death in Devil Bunny Needs a Ham.
You can find yourself having wandered over that line without knowing it, or noticing it - but one you're there and you think about it, you know. It shows in your behavior, if nothing else.
Sex, fortunately or un, is sort of parallel to this, or a top stripe, or maybe interwoven. Meaning it influences, compicates and obscures the entire question.
Different people travel up and down this scale with more or less ease. Different people act on their feelings to a greater or lesser degree, and with greater or lesser degrees of ease.
For me, the most difficult thing is knowing that I am loved - both just in general, and specifically realizing someone is interested in me more than casually, more than 'as a friend'. I can usually spot it in how other people feel toward each other, but I have a huge blind spot when it comes to myself.
Also, once I've crossed the 'line of death' so to speak, it's pretty permanent. Even if I come to dislike someone later, there's still that core. Well, I should temper that with admitting that if what I've fallen in love with is an illusion, it's the illusion that I continue to love. If it's potential that I've fallen in love with, and that potential is extinguished, that helps kill the love as well.
Love is not necessarially reciprocal, and as much as it hurts, requires no answer. It doesn't mean anything other than that you love the person you love. There's no guarantee they love you back, or even like you. It's wonderful if they do - it's magical if they do. Sometimes it's magical if they merely pretend they do. But love doesn't compell a response. It just is - you can act on it or not.
Babble babble random. Moving on now...