Hello stracie: Well... obviously the Skeezyks doesn't know anything about what is going on with your partner... what it is that is causing his paranoia & sudden mood swings or how serious they are. In general, I would say that there may not be much you can do about them. He needs to take it upon himself to figure out what it is that is going on with him & what he can do about it. In other words, he needs to take responsibility for himself. If your partner cannot, or will not take responsibility for himself, there may not be much you can do to change him.
The important thing here may be for you to do what you must do to take care of yourself. This might include getting some therapy for yourself, joining a support group, or just making time to get out with friends & do things that help you to feel good about yourself. There is a danger in these types of situations that whatever it is that is going on with your partner may end up dragging you down as well. This benefits neither of you. Beyond that, knowing as little as I do with regard to your situation, this is about the most I believe I could suggest.