Just tell him how you feel, he might like this other girl better and if he does it's his loss. But i'm sure you'd rather him be happy than hurting! Hope that helped :)
yes
If a guy tells his friends that his girlfriend is quality, he means that she is a great girlfriend.
you can tell him, or his girlfriend if you are friends with her
Tell him about it or tell his new girlfriend or you can make him jeoulous
It shouldn't be if the guy loves her back.
it means he want to show off to his friends he has a girlfriend
Cheating
Flip your hair and laugh with friends.
ask him, or ask his friends
Dump her, if shes cheating on you shes not worth it. Once a cheater always a cheater. My ex girlfriend cheated on me with a guy and i forgave her and after we broke up, i found out from her friends she cheated on me with 6guys including my best friend.
He already considers you as his girlfriend, or he's just bragging to his friends.
The best explanation is really just to show off to his friends. He doesn't wanna seem like a loser to his friends so he says your his girlfriend