DH and I have been struggling on and off for years; we are currently having marriage counselling for the 3rd time. Same old problems which just cycle around.
Last week was a moment of clarity when I/we came to the realisation that most of our issues stem from the fact DH clearly displays ADHD traits and the increasing fractures in our marriage it causes. After we spent most of our first few counselling sessions airing all our grievances. I jokingly said that our friends think DH has ADHD. The therapist looked straight at me and said they may well be on to something. Alongside counselling she also specialises in neurodiversity so I trust her opinion.
A few examples of behaviour he exhibits:
I have always taken on the mental load of home/kids/life admin/social life. As he has become increasingly unreliable I have taken more and more on my shoulders. Doesn't remember important dates, prioritise me or DC. There is literally not one thing outside of work he takes responsibility for. For years I have felt like a parent, not a partner.
I cringe when we are out with friends (always organised by me, he doesn't really have any friends). iif he's sober I barely get 2 words out of him; if he's had a few drinks he says the most inappropriate, embarrassing things. There is no inhibition. I have narrowed my social network as its such hard work being out with him which leaves me so lonely.
He runs his own business; he does work hard, too hard, but IMO is only just kept afloat as his deputy is such an organisational superstar. When we first got together he said he hated working for other people as they "just don't get me" and so struck out on his own. Possibly the last thing he should ever have done but we are where we are.
He is utter chaos at home; leaves anything and everything laying around. Always losing things and expecting me to drop everything to help. Only does any cleaning or tidying if I explicitly ask. It is like having another teenager.
The list is endless and I've been dealing with this for years; I'm exhausted. Having read up on ADHD I recognise "spouse burnout" and literally feel I would be better off on my own.
My resentment is overwhelming, yet he tells me all I do is nag.
I suppose he could get an assessment (at great cost) but I don't know if at the age of 50 it is too late. I only wish there had been this insight into neurodiversity 30 years ago when I met him. I found him quirky and passionate at the time but think I would proceeded with caution 
Not sure what the point of this thread is but just needed to vent. We are seeing the therapist tomorrow and hoping she can help with a way forward. I don't think DH has ever considered he has ADHD and I'm not sure he would take steps to investigate it further.