Bi-sexual girlfriend - what do guys think about that?

Actually this is my situation. She hasn't told me yet, but she told a mutual friend and it got back to me (first point ladies: tell the guy. and that works the other way around too no doubt)

my response is not the "Yay! Threesome!" response at all. To make one point: this is not because of homophobia but for the reasons below.
I'm not worried about guys. I know that if it comes down to another guy and me, It'll be no contest as to winning her over, but with the ladies it's whole new territory. Someone mentioned how now, the WHOLE world is competition. True, and on top of that fact, girls bring something to the table guys can't, and that's a situation where I can't confidently say I'll win out.

Beyond all that, I'm a little worried now that no matter what I won't be able to fill all her needs and that she'll be more likely to seek girls out on the side (and I'll consider that just as bad as seeking out other guys)

If any girl is in this situation, you gotta talk it out with your guy. You gotta let him know that he's the only one, no matter what gender, or, if that's not the case, then let him know he's gotta make some decisions on how he sees your relationship. For those girls who have a boyfriend just say "SCORE" I don't know if that's better or worse. At least then you wouldn't have him as upset as I am. Basically, you gotta talk this stuff out.

My girlfriend is bisexual, we are together for 8 years now, and I still do not fully understand what that means. Mostly because (I'm not complaining) she is committed. Right now I'm having my regular "what-if"-crisis. It is hard for us sometimes when it comes to long term plans.

It's hard to say, because every guy is different.
He might like it, seeing as how you are not likely to cheat with another guy.

Me and my girlfriend have been together a long time, and I've always had my fantasies about her and another girls(threesomes). It took me a while till she told me she is sort of attracted to that. So, we have our fantasies, and phone sex sometimes about that. But to actually do it! It's kind of hard to take it seriously. Yet in school she tells me that she checks out girls, or that she is attracted to them somehow, but not sexually, according to her. The thing is that I feel mad at that and in the same time it turns me on. I know its my fault, she warned me, but it's just fantasies. It's fun thinking and maybe doing too right, but I know ill jeopardize our relationship. Do you think she is turning bi on me?

My ex was bi, it didn't bother me until she started trying to see other people (including women) while we were still together. That ended the relationship pretty quick.

There's not a feeling quite like a girl turning you down because she likes another girl, but if it's a girlfriend, it would be related, but still different. Threatening, maybe, because now he has THE ENTIRE HUMAN POPULATION OF THE WORLD as competition. But I guess threesomes could be a resulting fantasy of that, and it depends on the guy, really.

I'd think "That's why we have so much in common, she likes women too!" I'm not religious and would be cool with what she enjoys. It's weird to me that a guy could think differently, considering guys are so creepily kinky sometimes.

I had a girl cheat on me for several months (I had no clue of course) and the way she did it was pretty immasculating to me. I didn't like that one bit.

But, then again, I'm a Christian who believes marriage can be a great thing and I've been for long term (one on one) relationships so that shapes my view of things. Similar to what Shanekokayne said, it depends on the faith and belief system he has.

It kinda depends on his religion.

He could become insecure, even if it is a turn on. Make it clear that you are committed to him, despite your sexually ambivalent feelings.

I would be really turned on knowing that she likes women and would hope for the threesome.

He'd either be turned on and hope for a threesome with another girl or get really worried that you'd leave him for a another girl. I had 2 bi girlfriends and one left me for a girl and that hurt, the other got me the threesome and it was awesome. Just let him know and if he leaves you just find someone better.

I am bi-sexual but a lot of people misunderstand what that means--it doesn't mean I'd want to have a three way relationship, in fact, I am only physically attracted to women but desire relationships with males. I have had a purely sensual relationship with women but found they are too nuts to date, so I wanted a relationship with a man.

A bisexual woman is not simply going to want to toss a girl in her relationships--it is more than about sexuality.

Okay so I am bi so I can straight out say that some guys are cool with it and others aren't. Some can't stand it and wanna fight and argue because you like girls. And there are guys that think it means they can mess around with girls because you are. And then there are guys who just couldn't care less if you do or not.