I don’t know if you should stay with your boyfriend or not but I can tell you this; if you or he expect different results in your relationship you have to take different actions.
First, if he wants to change then he had to speak with an expert. Usually, a psychologist or psychiatrist who specializes in ADHD and related disorders. If he doesn’t want to see a doctor, run! It’s probably only going to get worse.
For me, life was out-of-control. I knew I was badly depressed and had a severe alcohol problem. When I was 42 I started using meth heavily. A little more than two years after that, in 1995, I was finally properly diagnosed ADHD. In 1996 I found out I was also bi-polar. It was then that I started being treated properly for both. Since then, life has dramatically changed. No more ups and downs, no more outbursts of rage. My wife and I have literally not had an argument for several years. Occasional disagreements but no fights. What a relief.
This is how things worked out for me; I’m not suggesting that this will be your experience. However, hopefully, it will provide some inspiration. (Disclaimer: I’m not a doctor or medical professional so don’t take my work it, see a professional).
See, ADHD is a physical problem in the brain. And like a broken bone, it’s treated medically. With medicine. Bi-polar is also treated medicinally. Believe me, I’ve had no psychotherapy since 1996!
Once a patient is diagnosed and treated correctly, she or he will start finding out that ADHD can be a gift. But that’s another topic.
Good luck with your boyfriend and remember, you can’t be any good for someone else unless you take care of yourself first.