Why am I so sad when I know it's bad?!

My partner of almost 18 years now, is chomping at the bit to leave. He wanted to leave then agreed to stay to help support our daughter then changed his mind again. Now, when our lease is up soon, he will be off. He 100% has ADHD but was only unofficially diagnosed when our daughter was officially diagnosed. It was recommended that he go through the diagnostic process himself to make it official but he never did and has remained in denial ever since. He reckons he's fine and it's everyone else that has the problems.

It's a long boring story and no, we don't have a 'normal' loving relationship so why on earth do I feel so bad? I *should* be the one who is chucking him out, not the one who feels we should be trying harder to sort all this out. He displays classic ADHD traits and is difficult to live with. He has caused so many issues in our lives that most people would have chucked the towel in ages ago, He is incredibly self centered and is largely unable to see any perspective other than his own. We haven't been intimate in well over a year, he can't even speak to me in a normal tone of voice and he does nothing to involve himself in any of life's normal day to day family stuff as that is just too boring. Don't get me wrong, I have also been responsible for a lot of our difficulties but I have held my hands up and owned my stuff and apologised for it. He hasn't done the same. He says he doesn't love me and although he reckons he loves our daughter, his actions say otherwise. She will suffer greatly if he walks out simply because of the finances. (We have a very complicated financial situation and me and the kids will have to move and our daughter will have to leave school in this area because of this.), I don't want to go into details and I have got advice from a financial advisor so I do know the accurate ins and outs.

So, knowing that he has already emotionally detached from me/us and that he seems to value himself more than his daughter or her education (she's at an important time in her schooling and also only has 2 years to go), why on earth am I still hoping I can change his mind and make him see a child and nearly 18 years is worth fighting for? I wish I could be as 'bolshie' or determined as some of the posters on here but the reality is, I'm pathetic and I am cracking up.

I feel as if I've spent my life being there for him and I'm now being dumped and dismissed without a second thought even although he has largely been the shit over the years and I've been ridiculously reasonable. 

I feel as if this is so unfair and I am so frustrated that he doesn't see that. He refuses to even address the ADHD issue and he's not interested in trying. Even if he would accept how this is going to affect our daughter  then that would be something. How can anyone chuck their kid to the curb like he is doing? He says he can support her even if he lived elsewhere but he has no clue about the finances. He never has, he was in debt when I met him and I've sorted the money out our whole lives together, so he has no real take on the realities. There is no way we can divide our finances and successfully run two homes. Our daughter will be the one that suffers. She too has ADHD as well as anxiety and depression so this is hitting her (and her education) hard.

Maybe this is the wrong place for this post. Sorry, just feeling really low. I hate ADHD with a vengeance, it's got too tight a hold on the man underneath who I fell in love with. I am finding this all so hard and our daughter has mental health problems now because of all this, she is failing at school and has anxiety attacks and depression. Her therapist recommended her Dad and I go to couple counselling but he isn't interested and just wants out.

#feelingreallysad

​Has anyone ever brought their relationship back from the brink when their ADHD partner feels like the love has gone? Or do I just give up and try to deal with the sadness and loneliness and try to cope with the fallout with regards to our daughter?