I'm really sorry that this has happened to you and that you feel alone when you really need support. I have been through the procedure too and I know how upsetting it is, even when the reasons for termination are reasonable ones. I was "alone" too, although I had good friends around to help.
This is really long so if you want just skip to the list at the bottom
I think you need to deal with the fallout from the termination first and get through the hormonal ups and downs because while your body is readjusting you shouldn't try to handle anything else that is emotionally exhausting. This can take a while - certainly at least a month. When your body has recovered, you can make better decisions that aren't hormonally driven.
Having said that, I have a couple of observations. I have learned (mainly through trolling the poly forums, lol) that most relationships do break into two categories: primary, and non-primary in different degrees. I also learned that these labels shift over time, with people moving from, say, co-primary to secondary to friends, then back again over time, the point of poly being that when you have a connection with someone, you maintain that connection however it manifests in terms of a relationship. Sometimes one relationship requires more attention because of what is going on with either that partner or the relationship itself. That should be okay with everyone involved.
Poly is not something that can be said to have "rules" per se, but if there is one, I think it is that communication is essential. Communicating what is happening in one relationship that can impact upon other ones, for example. Explaining to his wife that you need him because of what you just went through, for example. She may not like it, she may hate it, but if she chooses to remain in a poly relationship (and she is in one, even though she sounds mono, because her husband is poly) then she has to respect basic principles of compersion - or even human compassion. It sounds like she doesn't. That is going to be a problem going forward.
So, in a nutshell:
1) Take a month to recuperate from the termination. Be kind to yourself. Do things you enjoy doing. See friends and family. Go to counseling for help.
2) Act, don't react with your relationship. Proactively tell him that YOU need some space to recover physically and think about what you want emotionally. This gives him time to "reconnect" with his wife - all the time he wants, because he cannot come running to you when he is not happy there. He will have to stay and work it out.
3) A new year is about to start - there is something to be said for eliminating things that make you unhappy before it gets underway.