I mean, most people say that if I bi person enters a hetero relationship, they're still bi. But what if I was never bi?

But I did like a girl once, but it was never that serious. Not as serious as the relationship I'm in right now...

Bis can be in both gender relationships, That's the whole point

XD

Theres no problem with being in a hetero relationship. After all you are attracted to males (assuming that your female or feminine gender)

You can still consider yourself bi, even if you're in a hetero relationship. As long as you still feel attraction to women and girls, you're bi.

I... err...

yeah same with me. if you still are attracted to girls, you're still bi

Ur still bi, bi means attracted to both genders