ADD or ASS?

This an earnest question, when someone makes decisions and takes actions that they are completely aware are hurtful and destructive, can it really be ADD, or are they just an a$$hole? And actually, does it even matter?

My husband has been diagnosed bipolar, and then ADD. He will not take medication. 25 years of marriage, 3 amazing kids. More job losses, financial stress and cycles of anger than I can describe. 20 years ago he had an emotional affair and we got through it with counseling and moving to another state. 2 years ago, he had another emotional affair. Back to counseling (couples and individual and he ended the interactions with the woman) and he began to accept that he has ADD, but wouldn't take meds. This year, I was laid off and all 3 kids were prepping to head out on their own amazing adventures - another high-stress time for all. I discovered this summer that when I lost my job, he reconnected with his "friend" from 2 years ago. (Despite several therapists identifying his relationship as an emotional affair in every sense of the word, he still categorizes it is just a friendship.)

This time I will not go to counseling until the "friendship" is suspended  - his counselor, mine and a couples counselor concur. He refuses to give up the relationship. He has moved out (to his sister's) and won't communicate with anyone about how he is feeling, what he wants, what he intends to do. The kids are devastated that he has chosen this path rather than attempt to work to any sort of mutual decision about our marriage. I feel no option but to start legal separation actions.

I recognize the impact of ADD and the inappropriately angry reactions that I contributed to the negativity of our marriage.  I'm still willing to talk and try to work on some sort of relationship. However, his choice to continue a relationship that causes me pain and to put it at a higher value than our marriage and family doesn't feel like ADD. It feels like he is simply an a$$hole. 

I've talked with several other women who have similar stories - bad behavior later categorized as untreated ADD, but by then the relationships are destroyed. 

Interested to hear thoughts and insights from the forum.