OP I have bipolar and what you describe does not sound like it. If it was, it should have been picked up by the gp and the counsellor. I am not trying to do a diagnosis online by any means! but bipolar 1 is characterised by manic - and I mean completely inexplicable - highs, and black, black lows to the point of suicude (the latter which is also bipolar 2), punctuated with periods of paranoia and anxiety. There is rapid cycling which is where episodes happen every few months, whilst with the former two you can have years of relative stability followed by months of mania buzzing round like a spinning top, and then crashing into depression and not even being able to speak.
Untreated, it can essentially kill some people and completely ruin lives. Treated, people can live happy, functional and fulfilled lives with these families, hold down jobs etc. If you have the chance, Stephen Fry did a wonderful documentary on bipolar I think back in 2009 that you may find interesting and helpful to watch.
I am sure with your DH it is something more psychological, perhaps punctuated with episodes of depression? It sounds like extreme trauma he suffered as a child - has he perhaps got Borderline Personality Disorder (often shortened to BPD) or Post Traumatic Stress Disorder (PSTD) or something like that instead? I have BPD traits due to sexual abuse as a child and have had to receive extensive psychotherapy to work through a lot of behaviours that were very hurtful to my DH. Disassociation ie disconnecting myself from everything around me and not communicating was one of the main ones. The other was a flight mechanism where I would just walk off and not speak.
Tbh I can understand your Dh's wish to not have anything to do with his family. I didn't speak to my mother for months as I worked through the extent of what happened and her role in my growing up. To this day I don't talk to her much any more. My life is much easier as a result and less stressful. If it is too much of a trigger for your dh it is actually better for him to not have contact until he has worked through it all and made a decision on how he wants to proceed.
I mention PSTD as a friend who went through what your DH did as a child and teen has been recently diagnosed. It's just something else to consider.
My DH got depression last year looking back. He got frustrated with always having to be my rock. Before I got my diagnosis and started treatment I was in a terrible place with bipolar and totally dependent upon him for everything. It was then a further six months or so before I got the psychological treatment and a long difficult time for him. After every session I wouldn't talk for a couple of days. Essentially you are reliving your childhood trauma and it is incredibly difficult. Husbands and wives aren't allowed in sessions - my dh wasn't anyway. Your H may also have been advised to not have other forms of counselling right now.
It is easy for us to forget the poor partner on the receiving end sometimes as we are in our heads going over the scenes of abuse again and again, but not wanting to. It's pretty horrific tbh. And then the brunt of that is taken out on the ones we love the most.
Stress is a massive, negative, contributor to someone with a mental health condition and really shouldn't be underestimated in making a person sicker. Has there been an increase recently?
The above is just me sharing my story to give the perspective from the other side :) All of the above doesn't alter the fact that you are struggling. It is very important that you take time out for yourself, and even access counselling if you need it. DH tends to internalise everything and didn't and I wish he had. When I was/am not being me, he knew though, that I loved him and when I returned in my head I would tell him so. He also read up a lot on bipolar and BPD so he knew what to expect.
It is a definite positive that your DH is open to treatment. But he definitely has a communication problem and should be looking to you for support not cutting you out. Is there a way the two of you could get away for just a night and explore the concerns you have in a non-confrontational, supportive atmosphere? Leave the kids at home and take time for the two of you?
It is entirely possible to have a happy, fulfilling relationship with someone who has a mental health condition, so long as that person is working hard to self manage (getting treatment, taking medication and therapy) and there's compassion and understanding on both sides - and always communicating openly and being upfront, always. If I have done something to upset DH he let's me know. He's not precious around what to say any more. I wonder if you feel you can't say anything for want of making him 'sick' or 'worse' etc whilst because he has something wrong gives him licence to be pretty rude? That's not acceptable.
It's hard work, but then any good relationship is. If you feel you are not getting this, or there is no hope then you need to reevaluate what you want. Only you know where to draw the line in the sand as to what you will put up with. And you know what, if you feel you aren't getting what you need from your marriage you have every right to start afresh. Mental illness is not a free pass to behave like a dick - yes it can cause very strange behaviour but there is nothing stopping him from saying sorry afterwards and making you feel wanted and loved.
The mental health boards on mn are excellent too if you wanted more advice. Sorry for the massive long post but I hope there is something there which might be helpful.