I am not BP but my partner is. I have read books on the subject, joined forums online about it and also attend weekly support groups for it too. I have learned that BP has different stages and symptoms. Yes, rage and anger are definitely symptoms of an episode.
You've taken the right step by joining HW as there are very informative people here that are willing to share their own experiences as a form of helping another out. This is really a great place to educate yourself. However, it's not the only source to be tapped in order to learn more about BP. Reading some books on the subject and joining a support group can really help.
If you'd like, I can offer up some great books to read as well as other websites supporting BP and depression.
Unfortunately infidelity is another symptom of mania episodes, but this is not the case with everyone and while it may be suspected, the best thing to do is believe innocense until proven guilty....as hard as that may seem to be to practice.
Reading your post, it sounds like your spouse hasn't seen a doctor yet regarding his illness. Has he been dx by a doctor yet?
Describing the different moods he exibits, sounds like classic BP, but I am not a professional so it's only a guess.
Try and take care of yourself an hang in there..
What you wrote sounds so much like bipolar to me. The doctor needs to make the dx of course, but it sounds so classic. The anger is definitely a part of all of the bp symptoms sometimes. It's definitely there for me. Bipolar is really an awful thing to deal with and live with.
It's got to get better SW, it has to; it will. Hang in there.