My ruined marriage due to undiagnosed ADHD (non-ADHD wife)

I've been with my husband for 18years, dealing with undiagnosed ADHD (diagnosed this year). I thought my relationship was "normal", challenging yes, but challenges all couples face. 

Aside from the standard mis-communications in ADHD/non-ADHD marriages, the interrupting, the impulsiveness, the forgetfulness, i've also had to deal with sexually explicit messages to another woman (2mths before he proposed), marijuana misuse for 16years, messages to an ex girlfriend (4mths prior to the wedding), getting fired for gross misconduct (2years ago: sexual harassment, racist jokes, homophobic jokes). Following him getting fired, I helped him with his HR process and he ignored me when i told him to resign (as he frequently ignored my opinion, as he couldnt comprehend why i thought differently). The worse thing is i thought this was normal behaviour. He passed it off as a joke, that there was no intent to hurt me and theres nothing happened "in the real world". Following him getting fired, he finally quit marijuana (as i had been asking for 10years)......and said he did it for me (he did it as he got fired). I picked him up, put him together again, boosted his ego, following him being fired when i could have divorced him. I expected a sorry and a thank you. And whilst he said sorry at the time, the following 1.5years he never really made an effort to go above and beyond to apologise. Instead he partially completed a dating profile (not active, so apparently no intent!). I found it and said nothing.....for 6months. Thats how in denial i was that this behaviour is normal.

 I sought counselling as i was having a breakdown. He didnt notice anything was wrong with not seen by him at all. My last straw came when he contacted a women on facebook late at night asking if she wanted to talk as she seemed down.......all the while im in counselling trying to find a way to move forward from him getting fired, and he never noticed! I confronted him about what i had found and was told he had no recollection of the dating profile and the next day all passwords were changed. In addition he has a very very low sex drive but excessive porn use.

I suddenly realised both my son and husband have ADHD and paid privately for my husband to get diagnosed first......after 3months of him dragging his feet. Im the main breadwinner. It was like someone had lifted the lid on my 'perfect' life. 

We are now temporarily separated and im calm. Im eating again. My son is fine (i never thought he would be) but i dont know if i should go back and try to work at it, following his diagnosis. My problem is those words of sexual harassment are too much and ive tried through counselling for 7mths to move past it. Any support would be appreciated. Thank you.