Motivation? I will say it again.

This is biology and a basic drive.We are talking about carrying on the species. Not love (whatever that is), togetherness, next steps in development of self or realtionship...reproduction of the genes (hopefully the best ones). That is why the doe looks for the buck with the best set of antlers or the lady mountain goat looks for the gentleman mountain goat that butts the other ones off the edge of the cliff.
We human animals should not think we should be so different. We are still animals when it comes to this. Go for someone who will maximize your genetic potential. Trust me, if you ask yourself this question your deepest self will answer *immmediately*. And if you have to *ask* your deepest self then he is not the one.