You have me sympathies. I don't know if this info will be of any use to you. I am new to bp and infidelity.
Being bipolar myself I would love to give you advice and insights. The illness varies so much from person to person though and as I have bp2 depression is my main problem. That means I do less of the mania things but I do struggle with suicidality. It means I can't really advise from where your husband has been illness wise, he sounds far worse than I have ever been.
I just wanted to say I think you have done an amazing job supporting you WH and I wish he could appreciate every single thing you have done for him. I am glad to hear he is accepting his illness and doing the right things now. Yes, you are his wife, but you can't fight his illness for him.
I can't really comment on BP cheating as I have never done it. I was diagnosed after a hypomanic period where hypersexuality was the main feature. This is TMI but it might be relevant. All I could think of round the clock was sex. If H wasn't around I was doing the job myself. All day every day. This was all consuming for around 3 weeks but with the build up and drop off it was more like 6 week. Sadly it made my H uncomfortable. Like it wasn't really me. IT was but a ramped up version. I got very angry if he tried to refuse me.
For me cheating would never have been an option but I do remember thinking if I wasn't housebound I would have been very distracted by any attractive man I saw. I would imagine walking down the street and grabbling any likely looking man.I am grateful I was in control enough that I would never have acted on it. But as the name suggests hypo (little) mania is nowhere near as bad as full blown mania which I am grateful never to have experienced. It's like being plain old horny but non stop and x1000.
I do know what it's like being out of control but never to a point where I would do more than fantasise about cheating, even that made me feel guilty!
It's extremely unfair you are having to deal with this double whammy.
Can I ask you to remember to take care of you?
You mentioned you had started to do things for you and that you withdrew from your H. The same thing happened with my H but he was the one who chose to cheat. Yes, I withdrew too cos I was learning to manage my illness but H withdrew cos it was too much for him. I thought by keeping a lid on my depression he wasn't being affected. Kind of it's ok you get on with what you want to do - I've got this, I can manage. So he did. Straight into the arms of another woman, someone he hoped he could talk to but almost instantly it became an escape.
I get angry about this, I never cheated, I never ran away, I tried to never drag him down with me but still it scared him. I have taken an overdose, I have been so desperate I have hit my head in things, punched doors and hurt myself. That can't be nice for anyone to see.
What I am trying to say is living with bp is difficult all round for the sufferer and the partner. BUt it's not the partners responsibility to try and make the ill partner better, just to support and understand which you have done admirably. I really hope you continue to have that bit of life you found that was just for you. I wish my H had done that rather than cheat.
You need to look after you first. PM me any time you like. I don't know if I can help but I am there if you would like to talk.