Sneaky link???

So i currently am in a hetero fwb relationship, but today I met up with a girl that I used to talk to but we couldn’t actually date bc we were both in a private Christian high school. However now we can. But I don’t want to come out as bi, and she doesn’t want a committed relationship. She wants sex. And I do to. But I don’t know if it’s wise. Bc, my fwb partner wants to begin a committed relationship with me, but I think I would ruin him. I think he would be settling with me. And really, I like the girl more. But she doesn’t what a relationship. Ugh. Do y’all get the predicament? What do I do??