Wait, what does he do? I don't remember him doing anything strange after my Tav's rejection. Then again, I stopped having him in my party the moment I reached exceptional approval and then he spent time alone with Orin. He still seemed to be into my chara during the epilogue party.
He will ask to join you with the Drow even if you are not in a relationship as long as he is in the party. Unfortunately there isn't a text-option for "You go have fun Halsin, we'll wait down here."
I never had the drow scene, because I never asked them for sex, but after I said no, he tried to worm himself in my relationship via my partner (in that case Shadowheart). His pickup line alone is creepy: 'You tended to my needs in camp like a lover'. Dude, I asked you, if you settled in, get a life. Needless to say, he ends up with Orin nowadays and I really sadly always botch the persuasion roles.
"We are all stories in the end. Just make it a good one."
