I think there's probably a higher chance of you having a boyfriend than him having a girlfriend.

People can be real dicks OP. I honestly would have slapped that asshole

Congratulations on your new relationship that's great! Unfortunately the world is full of micro aggressive dicks. This likely won't be the last or worst comment you hear.

Been there. It is painful like hell. But remember one thing, nothing that comes out of the mouth of this stupid classmate is relevant. Their contribution to the world is zero. So screw them. I would have probably said "Yeah ME bitch". But again, ignoring them or giving them the "you're so stupid" look would probably be good enough. I will never understand people who go out of their way to deliberately hurt someone. It literally takes effort. Like.. Why? You have to be a very shitty person. Either way, you stay strong OP.

maybe he thought you would have a girlfriend?

"Oh shit, I was thinking of somebody else! Don't you hate it when you think you're a completely different person and in a relationship?" –Nobody ever

That guy was a total jerk. Enjoy your relationship and don't worry about what people think!

He's just jealous. Be proud OP

Its okay, he's just lonely, his hand will make himself feel better later on.

That's when you ask where his girlfriend went