You are asking for tips, about the only thing I can think of right now, is that what you must already know, perhaps without realizing it though, that this situation is not good for either of you, it can't get better, because it is what it is.
You both deserve better, I think you need to find a way to take care of yourself, before it gets worse. I can't tell you what to do, but if it were me in that position, I'd be gone, not wanting to do harm or be harmed.
Stay on the safe side, don't let something just happen, jealousy doesn't get better, doesn't improve, in my experience it gets worse. You cannot change him, and it's difficult to change ourselves. The main thing is to prevent the situation from escalating.