husband is bipolar?

I really think my husband may be bipolar. It runs on his side of the family and I think it could be a big part of our issues. I've told him numerous times that I would like him to speak to a dr and get help but he refuses. I don't know what else to do. His mood swings are tearing us apart more and more. We have a good period then it's like a switch flips and he's angry and yelling then a few min go by and he acts like nothing ever happened and wonders why I'm pissed.