If it was a hickey (which I'm not at all convinced of btw) then its safe to say you have thee stupidest bf in the world.

Firstly you can feel if someone is giving you one, so if its not your gf, its stupid to not stop the alleged hickey giver, secondly, parading your alleged hickey is just stupid AF unless you want to be dumped, which in a manipulative way is then kind of smart if you think about it.

But since he doesn't want to be dumped....

Either you have trust issues or your boyfriend is dumb as a rock.

The first I would suggest working on strengthening your relationship, the second, well, different strokes for different folks. Even dumb people deserve love. Not that you have to be the one to give it to him, that's up to you.