Because it is tradition and so not romatic otherwise?
I have often wondered what romance really is, and what it is based on.
I spent most of my life being completly unromantic and quite happy with that, and then met an Irish sub :-)
I got over most of it, but not entirely ;-) In many ways still like a foreing language to me, or a colour I cannot see...
I can see a proposal by a woman as equally romantic, though. Easily.
I can even see both getting the idea at the same time! Uhm!