LOL - that's an infinite regression...

Sexual attraction is an emotion, yes.

But then all emotions are physiological reactions to outside stimuli or lack thereof. Therefore, it's all, at the root, biology.

You can try to play either the absolute materialist or the absolute idealist; but by trying to be absolutely reductionist, you become what you tried to disprove...

I don't necessarily always agree with what I'd call the GLer Nicene Creed, but it is quite clear in its propositions and doctrine. Lindsay and Norbert in particular wrote from it and preached from it. You'd certainly do well to read Norbert's pamphlet...

It should be simple enough: do you want to spend with her as long as it takes you to get laid, or 24/7??? That's it.

Of course, it's never that simple - I know that. Most of the time people won't fit into either extreme. But as far as definitions within an admittedly infinite palette can go, that's about as good as can get.