How about i see him once more and let him know that i am uncomfortable and that if it continues i don't want to see him anymore? The only problem is i am trying right now to get accepted back into uni and i need letters and certificates from him, so i don't want to upset him just yet.

I don't think he would hurt me, he's, to be honest, probably not getting enough from his marriage at the moment. That's a good reason why a married professional would flirt.