Wife very emotional- rarely happy

My question is basically this:

My entire married life i have thought that i carry a certain amount of responsibility for my wifes happiness. Since i have been in SCS i have realized that happiness is her job and not mine. Yes i am a decent human being that provides well, is involved in sharing house hold duties and raising the kids, but little things trigger her often and set her off to be very irrational. My thoughts used to be whats wrong with me, im not perfect, and i struggle to make her happy. I know think she is bipolar, orni think poor thing she struggles with controlling her mind. Nevertheless i dont enjoy being with her and i am not sure what thoughts i should be going for.