Cadesmom is so right. It's time to be Cat and drop the rope with H. I too said:
"I have tried so hard to please him in every way" I haven't read your sitch in depth, but you are the responsible one in the R, right? If something needs to be done or fixed, he can count on you? Do you live a fair amount of your life doing things because they'll please H, or not doing things because they wont please him? If so, thing about this dynamic and please try to change it. If I'm off base, and that's not the case with you, ignore this and my projections here. I picked up responsibility for everything that H couldnt/wouldnt do. I wore myself into the ground trying to be loveable enough. It didn't work. No matter how perfect I thought I was, H was incapable of loving me as long as he felt a failure as a husband/father. His feelings of guilt and failure were his focus. Me? He could just take it for granted I'd take care of things, and he started to expect me to do that. I responded by doing and changing more. I lost myself. He looked at me and did not see a strong, happy woman. He saw a woman who believed she had to earn his love.. he started to believe that about me too.
"He was always too tired for me" - This sounds like depression and depression does not go away without treatment. People don't understand that the chemical changes involved change the way our brains work and the damage can be permanent. If you or your H thinks he's suffering with dep., it's very important that he see a Dr. It makes me SO sad at times to think of all the battles we've lost in our R just because depression was making it impossible for H to think clearly. There was no way he could have a R, communicate or find happiness without help.
"him and OW have been going at it like there is no tomorrow" - this really sounds like an addiction and that OW is his drug. Self medicating his ADHD and possible depression? It doesn't mean that she excites him more or has better chemistry. It just means that contact with her increases the "feel good" chemicals in his brain, just like a drug addict.
"I still treated him like a child" - Do everything you can to kill this dynamic in your R. If he thinks your mothering or treating him like a child, that's not good at all. I used to say "well, you need me to treat you like this because you're acting like such a child!" I was wrong. The first thing I had to do for H to be interested in me as his wife and lover was to not mother him. I still struggle with this and if I start taking care of him like a child, it immediately causes problems. Men don't want their wives to tell them what to do, control them, or mother them. Period. Even if they are way screwed up and irresponsible, they'll run from control/mothering.
"my search for affection was too much to deal with" - yup.. heard this too. This comes from him and his feelings... guilt, failure, lies, cheating. They don't want us to come too close when they're hiding or when they've cheated. Being close to us makes them feel bad and reminds them of what they've done. If they don't have to feel anything, it makes it easier to run from wwhat they're doing.
Anyway, sorry for the long post. Just wanted to share what I've been through in case you can find something that will help in your sitch. Listen to CM and get back to the strong, wonderful woman that you are. Drop the rope and let him deal with the probs he's created. And, above all, encourage him to seek med help.