I agree you should go to his therapist with him. Take it slow and realize you need to be patient with him. Mania brings out a whole different aspect than depression. You may want to find out things from him if he is willing, such as if he has paranoia (which can turn into issues if he suddenly has paranoia about you.) Maybe ask what his pattern in depression has been, (isolating, sleeping a lot, not getting things done, etc.) So you can have some awareness.

I'm married 8 years now and have 3 kids. I'm untreated and you know, it can be a bit of a rollercoaster. But my husband and kids are really important to me and my wellness. So, even if we have some challenges thanks to me, it's totally worth it.