If you think there's more for him to admit, there may be more he can't remember. I know when I'm manic, once I come back down I have huge memory gaps and the whole thing seems kind of surreal and hazy.

I don't have a lot of experience with navigating relationships or marriage with bipolar, but maybe getting therapy together would help? The therapist could help you understand bipolar disorder better and could help you come up with strategies and a game plan if this happens again.