wombat-- I cannot deal with my girlfriend being bisexual at all. I just try to keep it hidden. i am a paranod jerk, and I hate it. but I keep it inside, because otherwise she gets really upset.
its mostly her fault, though. She cannot understand that I don't like hearing about anyone she's dated/kissed/whatever. I don't care if it's a girl. or a boy. I just don't want to hear it. And normally she remembers, but then, in public, with my friends she'll be like "yeah, I totally got it on with that girl", blatantly.
or make jokes about the time she cheated on me with some girl. and then not understand why it makes me mad.
it is upsetting. But I try hard to not be a dick about it. I'd be more OK with it if it weren't for the fact that she can't restrain herself. I am sometimes attracted to other people-- but I don't feel the need to go into graphic detail about it every single time I see them. "oh god, andrew, every time I see him I get weak in the knees *makes little sighing sound*".
Not to mention the "would you mind if I (dated a girl/kissed a girl/whatever)?"
Some people just can't take a hint. and I try hard to tell her no in a way that doesn't come off the wrong way. But I probably fail sometimes.
So, in conclusion: yes, it is very upsetting.