It has been said (and not by me) that the following statement is true:
A man will date/marry the most attractive woman his income can attract; and a woman will date/marry the most powerful/wealthiest man her looks will attract.
From casual observations, that statement holds a lot of water. Not necessarily in every case (assuming this statement does not apply to you), but it seems to be true more often than it is false.
And my casual observation says it does not. It is not applicable to me, and I have found it to be false more often than true.
I'm not saying it doesn't happen - I just don't think it's all that common.