Jen,
You obviously care for this man. The most loving thing you could do for him right now is to start setting boundaries. While you are putting up with his mood swings etc etc he will continue because he has no reason to change. He figures, she's not giving me a hard time, she puts up with my crap, she will be there in the morning, so why would he be bothered to do any different. Its like a child who misbehaves, you know, a tantrum, I want, leave me alone. If you let that child continue to behave in this manner what do you think you will have in the end. One spoilt child who gets their own way and it takes a lot of work to repair that.
Good luck to you.