Is it possible for a bisexual person to be in one relationship

Of course they can, how silly. A straight person can be faithful even if they want to fuck another person of the opposite sex. Same with gay and lesbian people. If you want to be with that one person only, you will stay with them.

A bi sexual person is just as likely to cheat or want to include someone else as a straight person. Bi sexual people are able to fall in love, like any other human, thus making them want to maintain a faithful, loving relationship.
Bi sexual people are humans. Not sex driven, sex obsessed, predator robots.

I don't see why being attracted to a wider range of people would make it harder to be faithful. I like girls with dark hair and girls with fair hair, but that doesn't mean I require two girlfriends to cover my range of hair preferences. So why would a bisexual person require two relationships to cover their range of gender preferences?

This question is so naive. I'm bisexual, and of course I can have a serious relationship with someone without cheating on this person. I'm quite faithful, actually.

I literally have no idea why the fuck you would think that...I mean, it's completely absurd.

I don't see why they'd have a problem with it unless they were non-monogamous in the first place. Someone's preferred relationship style is completely unrelated to their sexual orientation.

Being bisexual means you like both genders, and you'd date both genders, not that you'd date them at the same time. If you think they don't want a relationship with one gender because they want the other too, think of it like this: it would be like dating someone who can't stop checking out others of the opposite gender, except with a bisexual person they would just be checking out every good-looking person.

So you are saying it is impossible for anyone to have a monogamous relationship? Straight and gay couples won't cheat because they are already having sex with a gender and they will desire no others of that gender?
What a crock of shit!
If one is a mature adult and enters into a relationship with another person, then they are choosing not to have sex outside that relationship, not matter the gender.
Sounds like someone is just looking for an excuse for a three-way. Stupid risk of a good relationship, if you ask me.

*facepalm*

Dude... Are you retarded?

Anybody can have a serious relationship without cheating.

Fucking idiots these days...

You are an idiot.

You're not serious? I'm glad most of the commenters have some sense!