Can they change?

My husband and I have been separated for almost 2 months.  He pretty much abandoned me and all responsibility.  I had no choice but to check out and go into survival mode to take care of me.  I was left with no choice other then to detach myself from him so that's what I did.  Now he's begging to be with me, being the nice, gentle, affectionate, attentive.  The man I saw I got glimpses of when we first met. 

My mind knows its temporary.  I know he will revert back to his crazy ways and hate me once again.  I know he will spiral out of control and say that he can't be with me nor can he control his impulses.  My heart wants to believe the sincerity and save the marriage because I do love him and miss him.  It's like my heart is blocking out all the bad AND it was really really really bad, destructive and toxic.

Can someone with ADHD change or improve?  I just need to hear what I already know from other people I guess.