Oof. This hits close to home. I have ADHD and my partner recently ended a nearly six-year relationship, for several reasons (as it would be with any long-term relationship where you were planning to get married), but feeling neglected and like she had to constantly compete for my attention was one of them. Neither of us really explicitly/consciously realized this was one of major sources of unhappiness/friction at the time, at least not until close to the end. I don't blame her though. Looking back, yeah, wow, I really wasn't doing a good job of paying attention to her and her needs, even though I cared so so so deeply about her. Lessons learned, I suppose. I know now that this is something to be mindful of and put active effort into counteracting in my next long-term/serious relationship.