I have limited experience on this...I will say that my dad pretty much "got around" when he was younger. He was pretty crazy. What I can tell you is that when he got with my Mom he was incredibly devoted to her and he said that the relationship they had was plenty enough for him to give up the other women.
My Mom died when I was an adolescent. My dad remarried afterward to a woman I wouldn't have chosen for him, but I have no indication that he isn't totally true to her.
I don't think that having a lot of sexual experience is a straight line to not being able to give it up (given the relationship).
It does concern me that freakyfashionista is so consumed by this. If it's a problem to you...really, then he's not the right guy. But you can't fault him for being honest about it.
Personally, it might raise my eyebrow, but I don't think I would see it as a show-stopper, unless I saw some behavior that would suggest that he hadn't given it all up to be with me.
Just my 2 cents worth.
Jasmine