I’m a couples therapist who specializes in treating couples affected by ADHD. And let me start by saying, of course you’re not a you-know-what. You need him and you miss him, and constant videogame playing gets in the way.
It’s good that the two of you were able to come to an agreement that the main gaming system would not be played until the weekend and when he has accomplished his daily tasks. That shows that the bond between you is still working.
What I’ve found is that people with ADHD have an even more intense reaction to the feeling of being judged, criticized or rejected by their spouses than neurotypical people do. I am absolutely sure that rejection-sensitive dysphoria, which Dr. Dodson identified, is a major symptom of ADHD. It probably has to do with our whacky dopamine system. It takes more stimulus than it does in neurotypical people to feel that other people think well of us, and our batteries of good feeling run out more quickly. RSD causes absolutely horrible, visceral feelings of pain. They literally feel wounded — and brain scans would probably show that this is the way their brains are experiencing this.
So the best way to get him to become less attached to his video games would be to share with him that you need his presence, that you need him and want to be with him more. Not in an angry, shaming way, because if it comes across as either anger or judgment (or “you’re hurting me”), that’s all he will see it as. Adults with ADHD are secretly desperate for praise and approval, because of their low dopamine levels, but it makes them feel ashamed of themselves that they are like that, so they rarely admit or ask for words of praise and appreciation anywhere near as much as they need it. The gaming system is a quick reward system — it releases dopamine. But so does a compliment to him, a sweet word, something you say that shows you appreciate him for something.
You can say that you shouldn’t have to do all that, and I realize you are working really hard already and just wish he could step up to the plate more. And that’s fine. If you can phrase that in a way that doesn’t put him down, you’ll get through better. As in, “Sometimes I get so tired. I’m not always strong. I really do need you. I like being with you, I really do, and I miss you when you’re on your game. I start to feel really bad about myself, like I’m not interesting to you anymore.”
Then listen to him, listen to his struggles, assume that he wants to be the most loving husband and father he can be, but that ADHD is getting in his way. You can work on some interim step — some reduction that he feels he can do. Then be prepared to help him stick to it, just as you’d help someone who’s trying to give up cigarettes or midnight pints of ice cream — calmly, with a minimum of anger.