Am I bad?

Okay...so...I'm in a relationship and I met this guy on this app (it wasn't a dating app or anything) and he started out as just a friend. But then I started to like him and we started sexting and I feel bad when I say this but he turned me on more than my boyfriend. Then he became a fwb when my boyfriend and I broke up (I didn't tell him about this guy). And now, my boyfriend and I are back together but is still have feelings for this other guy. And I read somewhere that if you really loved the first, you wouldn't have fallen for the second so choose the second. And tbh, I really don't know what to do.

And also, my boyfriend is in the hospital and I don't wanna ditch him.