sex, definetly.
relationship.....that would mostly depend on what type of a person she was, how well i got along with her, etc. it'd definetly be an interesting situation, and as long as the sex was good and we had fun together, i'd be ok with it.
marrige wouldn't cross my mind at all. i couldn't be in my early 30s married to a chick in her 50s. i do know a couple in those age ranges that are married though. if it makes them happy, then that's cool.