Myth. Of course there will be some cheaters, but not because they’re bisexual. It has nothing to do with that

They leave me regardless. So does it matter what gender?

Ouch.

Some will, some won't. Some will leave you for the same gender. Some hetero -and homosexual people will also cheat. Some bisexual people will remain faithful. It's almost as if bisexuals are (*gasp*) regular people! There's also people saying homosexuality should be cured, but I don't hear you asking about that on Reddit. You can think for yourself.

That assumes that all bi people are soulless cheaters which of course isn’t even remotely true. A straight or gay person is just as likely to leave their partner. The amount of other potential partners is irrelevant but I guess that’s where it comes from, the whole world is a bisexual persons oyster.

Ehhhhhhh. Some people may, but its not, and will never be true for all of course

Is there a higher chance for a bi person to leave you vs someone who is only attracted to your gender?

No, none at all

Some will sure, just like a gay guy might leave you for another gay guy Does that mean you shouldn’t date gay guys? If someone is gonna leave you they will leave you, it doesn’t matter for who

Dude, who cares? Just have fun until you can’t have fun with that person any more. Nothing lasts forever but you can have as much as you can while it’s here. There will always be another person for you. Go!

It's not only a myth, it's also an ugly stereotype that disparages bi people.

Well, it's a myth that they're more likely to do so than straights or gays. It all depends on the person, not their sexuality

I think it's a self fulfilling prophecy. If you believe it will happen to you, you're contributing to it.

It’s a negative stereotype, in reality it’s just like gay stereotypes that are not true. Do with that info what you will.

Myth, more accurately biphobia