Why wouldn't she have asked for more details if they had a healthy sex life? To me it seemed like she was just curious and a little jealous of how Clark and Martha's sex life would have developed differently than hers and Philip's, but him not being the same kind of lover didn't to me mean that he was resenting Elizabeth for not being the same. Clark doesn't particularly like sex with Martha but I think he does like it with Elizabeth--not because of the sex as the person.

It's like in an early season of MM where a character tells her therapist, regarding her sex life, that sometimes he'll do something that she feels like is what someone else likes.