um... I dated a model and still slept around. she couldn't cook for shit....and I was lucky to get a bj even on a special occassion.
I dated a universally hot woman for 2 years and then started sleeping around. She was down sexually too. her bjs were not good though, she was clingy and depressive and it annoyed me
I dated an above average bi woman who bought home girls, I slept around on her too. she was 12 years older, I never took relationship serious.
I was friends with all of them though. I wouldn't have chosen one of the flings over any of them, but I don't think I could have been monogamous with any of them either.