Help!!

Hi, I am undiagnosed ADHD, my son is diagnosed and we are the same person. My wife and I have had issues in our marriage for years and have broken up and re-engaged twice, it looks like we are now going to split for a 3rd time and I am devastated, more so because she gave me this book and reading it has made me realise all the things I am guilty of, that I was unaware of, that has both had a massive effect on my wife's mental health and on our marriage. What I can't forgive myself for is the damage I have done to her mentally, even though I was unaware. My question to you all is... Should I let her go so she can go, meet someone else and hopefully enjoy the rest of her life, or do I get a diagnosis, start medication and fight for her? I'm not sure I have much of a chance as she has already said that I have once again ruined our marriage with my behaviour, but if there is a chance do I fight for her or let her go...