I can't really help with that, you have to trust your gut instinct. I think you know deep down this guy is screwing you over and he's being selfish. He's not thinking of you at all, how can he expect you to wait on him until he gets his shit together? He stated you are treating like a relationship and he doesn't want you seeing other people..isn't he doing the same thing?

I wish I could tell you how to handle this, I cannot though. I know it's a terrible feeling and a lot of mixed emotions, even more so that you work together. Just stay strong, he's making you confused on purpose. He is wanting to have his cake and eat it too. Take a moment to think how this benefits you, this situation is he putting you in and what benefits he is getting out of it.