I wanted you to know you have come to the right place for support on this topic.
I am not BP, but my partner is. I have heard many stories that are far worse than anything I have experienced with my partner and his illness, but none to the extent as yours. Yes, infidelity is something that is common when in a manic episode as well as irritability, and being argumentative. Threats of divorce have been known to happen too. But how you are describing your relationship with your husband does look to be more malicious than anything which I believe IS NOT a symptom of BP. A person who is BP and takes care of themself by taking their meds, seeing their Pdoc and therapist/counselor will usually have a fair amount of control over the illness. They are also very aware the illness is something that has absolutely nothing to do with another person! No one is to blame for the disorder...no one!
When my partner told me about his illness, I immediately took to educating myself with books on the subject, support groups, forums such as this one, etc. I did this so I can better understand it instead of trying to constantly rely on my partner to tell me what's going on. I also did it for support for myself and also understanding what I have in the road ahead of me, with us.
Finding HW has helped me incredibly with finding many answers to questions I have, venting and being heard and also trying to reach out to others when they are in need.
If you like, email me and I can give you some sources to tap in order to learn more about BP and possibly find a support group in your area.
Till then, please know we are all here to listen to you and support you in any way we can.
After twelve years of therapy my psychiatrist said something that brought tears to my eyes. He said, "No hablo ingles."