Yes.
When I was just out of college my girlfriend and I used to share an apartment with this roommate who was a raging slut. She was hot too, pretty, big boobs. She fucked a couple of different guys a week on top of her boyfriend who was clueless. Anyway she tried to get me a couple of times. Things like walking out of the shower not properly covered up and trying to snuggle up to me when we were watching TV and my GF was out somewhere.
I declined because she was also the low self esteem type and for sure if I fucked her sooner or later she would find away to let my GF know and rub it in, some sort of sick competitive thing going on with her.
So i was smart enough to say no, but man do I regret it sometimes.