Say to him you are not interested and he should be ashamed for flirting with you while having a boyfriend.

Iam doing that

You said it was their first time hanging out and they've only chatted online? That's not a boyfriend, no matter how much anyone would like it to be if he decided to flirt with you it's just best for him to tell your friend it was not working out... over time just drop that you're having some nice conversations with him and like each other

This.

This but I told his bf to give my friend more time and more hangouts

**** him and cut off ties with X. You'll find people will betray you no matter what

Have sex with him one or two times and then ditch both of them. Try to fake your death if that friend tries to go after you.