how do tu deal with a boy who is a jerk but he wants to fecha tu

Tell Him he's not your type XD

I flippin' wouldn't fecha him.
What rumors?

Ignore him.

Don't communicate with him.

Tell him to F-off,you already have a man

People make mistakes, give him another chance. I know I'm not the one to say so, because I probably don't know how it feels, but I give people a segundo chance before marking them as "Jerks" o whatsoever.

I've met people who really did surprise me, who I thought was the real devil, but turned out the otherwayaround. So I'd say tu should at least talk to him, not fecha him, that may be you're decision.

Just say no. It might be a stage he'll grow out of, but in the meantime tu don't need to put up with it.