I don't have AD/HD but my SO does. I know everyone is different and symptoms vary but these are my thoughts and feelings from being in this relationship.
My SO is the smartest man I've ever met. Intellectually and spiritually. He's charming, beautiful, and every one loves him. On the other side, what no one sees but me when we're alone can sometimes hurt. I hurt when I see him struggling with his academic studies. I know all of his marvelous ideas and how great he is, and to watch him painfully struggle to get through it because he has a hard time focusing is really painful sometimes. His mind works so fast, I have a hard time keeping up. One billion things are rushing through him every minute and sometimes it feels like it's hard to get close to him, and have intimate conversations cuz he can't stay still in his mind long enough for me to be able to explore his thoughts.
He's tried two different types of medicine so far in our relationship, and each time it's a struggle. I like what it does for him regarding his work and his studies but with each medicine I get a new boyfriend. It can be scary and I do feel lost before I get used to the "new him". It takes a lot of patience and understanding to be the SO of and AD/HD partner.
Hurtful things fly around, I try to give him the benefit of doubt and ask him what he actually meant by what he said. He usually has an explanation for it, he doesn't think like everyone else so things come out wrong. It works pretty well but I'm only human too so this can create conflict. Our biggest fights however has stemmed, probably, only from his disorder. Example: We would be having dinner, talking and he would just turn sour and start ignoring me or saying I'm acting rude of something. In these situations I have no idea what I did wrong and he can't explain what he's feeling. These things mostly end with me crying and asking him to please tell me what I did wrong so I can avoid doing it again, and he calming down and just feeling like an idiot. He's never raised his voice at me or called me names but it's always a bit like walking on eggshells. Will this trigger him? Or that?
It's not always easy, and I realize that he doesn't experience the worst symptoms, and most of all. I love him. I love the deep inside of him. I love his AD/HD too cuz it makes him who he is and I wouldn't want to change him in any way. This is real love. Acceptance. Patience. Compassion.