Yeah, I've noticed that too. Isn't it weird?
Nope - it's just your hormone levels dropping... :) Around 20 you wouldn't give rats a** if the girl was good with kids, but if she had big boobs and blond hair... later, say around 30, your hormones ease up and you start to look good mother / wife material and THEN (sadly) most big breasted blondes don't seem that attractive (mentally etc).