I absolutely do this whenever I go hypomanic or manic. I question my relationship big time. Usually I get through it by being honest with my partner. He is used to me saying we shouldn't get married, or that I'm thinking about us breaking up, and he knows that I'm sick at that time and it's not me actually wanting those things. I'm very lucky to have a partner who wouldn't give up on me when I say those things. Sounds like your husband is similarly understanding, and that you're doing good work keeping the instability from ruining your relationship. Keep it up - it seems like you really love him and can make this marriage last, even if you doubt it sometimes when you're not well.