“No. Shut up. If you really don’t get that I’m not going to leave you for the first cute guy who smiles at me, then I don’t know what we’re even doing, Ilya.”
Don’t be a butthole. Everybody can experience jealousy. It doesn’t mean he thinks you’re going to leave him, but it must suck to watch other people put their hands on you when he can’t. Try to be understanding.