I am so sorry to hear of your distress.
I read your message, my understanding is your husband had an affair , then it was over and your husband and work colleague continued to be friends for 12 yrs?
The key issues for me is
He is still with you
He has expressed remorse
He acknowledges it was a mistake
If I have got it right he maintained a friendship with this woman for 12 yrs not the affair.
It is difficult to deal with people who are upset, in pain, depressed because you care for them and it hurts us to witness that.
There is nothing wrong with you for having mood swings it’s called being human and Parkinsons is a tough in to deal with.
Communication is good and healthy in a relationship so good to let others know how you really feel. Its hard for anyone to be everything for everybody. Partners give love and support but sometimes it maybe you need a professional support network, counselling just for you see your G.P Or phone the pd helpline. Its ok to get help from others the more fighters on your side the better.
None of this is your fault don’t forget that and enlist a bit of help/support. You deserve it.
Think about what you want, and get stronger first. Relationships can and do survive affairs, look after yourself no rash decisions
One step at a time.
You have a husband who tells you he loves you and he has made a mistake.
Talk to a professional life is never black or white…
Its about what and who you want by your side tomorrow and in your future. Answer that then think about how you are going to remain happy with that choice tomorrow and in the future.
Take your time oxfordgills, I am sending you cyber hugs and love.
Love and support is a powerful friend in the PD battle. xxx