Is there something one can take to be positive all the time? Or happy?

My boyfriend and I believe that he may be suffering from bi-polar disorder, and this is seriously affecting our relationship (especially me, since he's back and forth wanting to love me and leave me). It's come to a point where he mood shift has left me hating myself due to his harsh words, and I feel miserable. He's admitted his problem and wants to seek help, for us. But is there anything that can help him? I don't think therapy will, since our issues run deeper than just mood swings- it's beliefs.

He might need some sort of medication to prevent him from thinking negatively, about past events and whatever else upsets him.

Please help!