I am going to step into the fire here I'm sure, but I've thought about this thread all morning.
Before I get beat up, I am not excusing any behavior that damages self and undermines the relationship, but there is always information that eases in that when a whole picture made, the corners get rounded out and if somebody struggling with far fewer years can glean even a snippet of wealth from a thread, it is worth the time to post.
AVR1962, you know I am one of your supporters as you worked through your own trials... and you know of my path as well.
Such said, when sunshineas shared that her son was ADHD diagnosed, that does place a different view to it whether one likes to see it or not. I'll not pose to know such a large picture in a thread, there is only a snapshot from the last three challenging decades, and while it may be perceived as unfair or ill-received, looking at the hows and why of relationship struggles, both from several views, one has to wonder how it plays into the overall and thus the healing to come.
Alcohol and cheating are destructive crutches no matter which partner has ADD/ADHD, thankfully they never played a part in my current marriage but in review of my past recognize that with compassion and empathy lost, was doubling down on what I knew best and lost myself to transferring the only tools I had at the time, which created a very unhappy and angry individual (myself), and made life miserable for others.
My wife is ADD/ADHD, my daughter severe with some BPD and depression, and from the stories my wife's brothers share... their mother and my mother-in-law probably more like my daughter. When my daughter struggled, my wife's surfaced and it was twice the battle to maintain sanity in the worst way... we were both where you are at 32 years at 16, and something had to change and I had created a codependent disaster, but it wasn't going to easily be the others to change, I could not control such. I compensated with walls, then learned to tear them down to stand open, with full clarity and unafraid...perhaps that is why I mention them so much.
So if I may ask @sunshineas
, is there a possibility you or your husband have struggled with this? Since many studies mark as high as 90% of all ADD/ADHD comes from one or both parents, has this played an unrecognized and debilitating factor in your relationship? It doesn't sound like understanding will stop the ending you face, but the important thing is that you need to trust yourself that you have survived a lot, and you will survive this, do not discount what may be the necessary elephant in the challenge you faced to help you land at the peace you deserve.
If you find my words too lofty and not fitting to this situation, I understand... but living in an ADD/ADHD household for an angry and reactive 70% of my marriage and having many years experience since learning to respond differently has opened so many healthier options.
Please remember to practice mindful loving-kindness as you finalize this part of your life, it makes great practice as you step forward on the new path.