On the one hand, I'd like to ignore this thread, since the OP is clearly just trying to brag; plus, I'd be really surprised if he weren't lying.
On the other hand, I actually like talking about this kind of thing, since I get the impression that I function counter to the mainstream (or, at least, stereotypical) guy, and as such, feel like I'd be adding something to the conversation. :B
I'm 26 and have been with 5 women.
Two of those were one-time things. And, while I was fairly certain I'd feel the way I did, those two confirmed for me that sex with someone I have no attachment to is, at best, unsatisfying (the other one, plain unenjoyable). This is in spite of the fact that both were, objectively, quite pretty.
One was a friend with benefits. Was fun, but something about the situation left me feeling kind of...uneasy. May have been the specific circumstances more than the arrangement; probably won't know until I find myself with another fwb.
The other two were girlfriends. By far, the best overall. Of course, we had more time to figure each other out -- I mean, one was my first time, and I was way too nervous to actually enjoy it, but it only got better from there.
I've got two hypotheses concerning this: first, closer/stronger relationship = better sex. Not even suggesting that a friend can't be closer than a girlfriend; that just hasn't been the case in my experience. Comfort around a given partner is probably a large factor here.
Second, based on what would seem to be a rather uncommon trait in guys, the less I know someone, the less attracted to them I am. I mean, I can appreciate beauty, but personality is a much bigger turn-on/off for me. Even my occasional celebrity crushes rarely cross the line into sexual fantasy -- I'm simply unable to think of them that way. The "stranger barrier" is insurmountable for my imagination.