Does anyone else who has become successful with girls have more difficulty trusting their partners now?

For me, when I was single and on the prowl, I ran into a lot of girls who had boyfriends. Not one told me upfront, some I'd find out later that they had boyfriends, some I probably will never know, and I even had one stop in the middle of sex saying she feels bad about her boyfriend. (Disclaimer: I never would have slept with any of these girls if I had known about their boyfriends before we had sex.)

So, now that I'm actually in a relationship, I always have this small doubt that if the right guy comes around, my girlfriend will do the same as these girls have done. It is admittedly a very small doubt and I trust my girlfriend, but it's still there and doesn't seem to be going away.

I'm just wondering if anyone else feels the same way, I'm not looking for relationship advice or a pitty party.