Well, to boil it down to pure psychology, the fact that you truly love and want this man probably has a good deal to do with the fact that sex with him is better than what you've experienced previously--because your emotions for him are stronger, your physical responses will be stronger and more positive towards him as well.

Either that, or he's just really really good. Either way, I am SOOO happy for you, and enjoy yourself! It's wonderful that you've found somebody this good for you.

luck&love,
~muse