How to tell husband we need to separate?

This year I found out I have ADD and I'm 99% positive my husband has ADHD. I understand our 15+ years together now more than ever. I don't have resentment, but I do not have hope that things will change with a simple request/nag from me for him to work on these things. He does not really believe in the disorder and denies having it, or says if he does his symptoms are under control (not true).

While I still love him and we've built a lot of amazing memories over the years, and have our two kids, I realize I've put blinders on most of the time (maybe my ADD makes me forget things too fast?!). I've ignored his lack of helping with house chores, starting but not finishing projects, low income; hyperfocusing on computer, games and other things; preferring other things to making love; and what I hate the most, his daily angry outbursts at all sorts of minor frustrations, but most worrisome, at our kids. I cannot just keep ignoring.

I have learned a lot about my ADD, I accept I have it and I'm looking for ways to improve. But he is VERY stubborn. Says everyone has their personality, not everyone can be like me and I should accept him as he is. I've accepted his ways for 15+ years, but with kids 6 and 3, not so sure I'm just willing to put my blinders on anymore. I love him, but he needs to accept these issues and work on them.

I want to tell him to move out to work on getting a diagnosis and treatment and he will probably be shocked. I want to make it clear to him that I don't hate EVERYTHING about him. If you remove all the ADHD (and possible ODD) chaos, he is the person I am in love with, laugh with and enjoy being around with, supportive of our children, a loving father. But all this time I keep reminding myself of the good/nice, while completely dismissing/downplaying the bad. But the bad hurts when it happens and I cannot just put it away in a trunk anymore and fear that things may be getting worse.

WHAT should I tell him, HOW should I tell him about this? I'm better at writing, than actually TALKING about these things. I choke up and need time to think through questions which I'm sure he will have. Please help!