My boyfriend has ADHD, and wants to go off his meds. What will it be like?

So my boyfriend, whom I love, has ADHD (diagnosed). He has been on meds for the last 10 years, and recently has thought about stopping.
When I first met him, he did show some signs of ADHD, such as hyperfocus on the relationship. He was very invested, and wanted to move fast. I discussed how uncomfortable I was with this, but also how I enjoyed the sentiment behind it. He understood, and backed down, which I appreciated. He's been this way the entire relationship. He listens to me, and gives me space when I need it.
He is very sweet, we have a lot in common, and he treats the best I have ever been treated relationship wise. I do worry though that when he is off his meds, things may not work out.
I have dated guys in the past who have had ADHD, and it didn't last. In fact the relationship blew up. I dont want that to happen, but I also want to respect the fact that he doesn't want to be on meds his entire life.
What could I expect if he were to go off his meds? And how do I go about warning him that it may affect our relationship?
My boyfriend has ADHD, and wants to go off his meds. What will it be like?
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