Is it fair for me to not feel comfortable dating a bisexual? I don't want to have to compare to the opposite sex & feel insecure.?

A bisexual girl is just as likely to cheat on you with another girl as she would with a man.  It's not a matter of being compared to the opposite sex - it's all about trust. 

If you feel insecure, that's YOUR problem.  You don't sound mature enough for a serious relationship anyway.

I feel the same way.

I'm a gay man, but I'd never be able to date or even think about a long-term relationship with a man who also slept with women or transgenders.  And it's not jealousy -- the thought of it just disgusts me!

I could never love a man's penis when it also goes into various vaginas whenever he gets horny.  Yuck!

Of course you've got every right to decide who you want to date, and who you don't want to date. Then again, though..? I seem to remember you saying you're in a relationship with a bisexual girl! That you love, and relate to in all other ways, apart from her being bi! Which.. of course you also have the right to break up with her, if you so choose! But I just think it would be really sad if you did so! As the two of you seem to deeply love each other! And.. that kind of love really isn't easy to come by! I think you're going to really regret breaking up with her! Especially if it's due to something as admittedly silly and superficial as this. Like.. her being bisexual, but not having actually cheated on you with anyone! If she cheated on you..? Then it would be fair to break up! If she demanded that you open up the relationship, or engage in a threesome with a man..? Then likewise! But literally her only "crime"..? Is: she loves you, and wants to be with only you, but she is also ABLE to feel attraction to men! Which.. that's quite a minor thing, in my opinion! That it would not be justified to end a loving, committed relationship over! Not to mention, it is not in any way her fault! As it is not a choice! And she cannot control it, any more so than you can just decide to like men, if you're a lesbian!

..Also speaking as someone who loves a bisexual guy, who's extremely in love with me, and 100% committed to being with just me! Bi people can be that, 100%! Them being bi does NOT mean they have to be with both men and women, simultaneously! If a bi person loves you, and only you..? They'll want to be monogamous! In spite of maybe occasionally thinking: "oh, that person is hot!" Just like you may occasionally think another girl is hot, who's not your girlfriend! But it's just a passing thought, right? You'd never cheat on her with another girl? Same too with bi people that are in loving, committed relationships! Literally the only difference..? Is, they may occasionally have those thoughts about both men AND women!

Anyway, my bisexual love says he does not at all miss being with men, because he only wants to be with me! And.. I'm also someone who's open to dating both men and women, myself! (Panromantic grey ace, here.) Who does not at all miss being with a female! Because the only person I want to be with..? Is my love! Which, I would feel the same way if he was female, too! Or intersexed! It's really not about what sex he is! It is about: "I love YOU, in specific! Just YOU!" And it is very much the same thing for him, too! So.. yeah. That's my take on this question, for today. Which, you seem to ask it a lot. It's kind of sad.

Just try to heal and be best for him little by little . Now no more tension he is with you . But to be honest your real threat is another girl that can give him everything a girl can give etc . Because that is more painful etc   like his gift etc it's too much etc so just try to be that person etc