I can't speak from the perspective of a bisexual or lesbian woman, but I have always been open to dating bi men and cursed the stereotype that bisexual people can never be happy with just one gender. Twice I have dated bi men, and both times sooner or later, they wanted to find a man to be involved with as well.
I know that they are not representative of all bi men or bi people, but I admit, after it happened the first time, it took me a little while to be open to dating bi men again. With the 2nd guy, our relationship got pretty serious. And for him, he was only interested in men for sex, and women for sex and relationships. It was tempting to swear off all bi men again, but I'm reminding myself that in case #1, we were young, and I think the guy wasn't quite sure if he had preferences. And in the 2nd case, turns out the guy had issues with commitment and monogamy anyway. So I'm consciously telling myself, as I look through profiles on OkC, "Remember, bi guys are no more likely than straight guys to have issues with monogamy and commitment, it's just a stereotype." It's taking this consciousness to combat my personal experiences and the stereotype that's been bored into my head.