I have ADHD, as does my wife. Here's what we've learned.
First and foremost, handle your ADHD. It doesn't just go away on its own. You might medicate it away for awhile, but it's progressive and it'll be back. You need a combination of strategy, lifestyle changes, and medication. A therapist experienced with ADHD is great, but literature exists if therapy isn't affordable.
My wife is a great example of what not to do. She never pursued therapy, doesn't take great care of herself, and never developed any coping strategies past popping more pills without taking medication breaks. Now she's at the maximum dose of adderall combined with strattera and it's not cutting it. Since her ADHD is out of control, she's having difficulty developing strategies to handle her situation and it is torture for both of us. Similarly, if you have any emotional trauma, get on that now. These things only become more impactful and harder to handle with time.
No one makes assumptions. We don't make inferences, we don't play guessing games, we don't try to read minds. If one partner doesn't directly request something, they have no right to be upset if they don't get it. If one doesn't directly state something, they have no right to be upset if it isn't understood. It's nice when my partner anticipates my needs, but it's unreasonable to expect them to.
Have regular, formalized meetings to discuss needs and the state of your relationship. Important communications are finalized in impersonal, precise, "business style" writing and made accessible. We've had far too many agreements that led to conflict when it turned out someone later mixed up details or never understood to begin with. We have a giant dry erase board in the dining room where important reminders are left.
What matters most is you're doing something now! My wife and I have been together for over a decade and she's only now starting to really work on her issues. I love her and we're still together. She's also not the sole source of issues, just the main source of ADHD issues, which is why she was thrown under the bus (for educational purposes). I contribute plenty, just as I suspect your partner does too. Don't beat yourself up.
One thing that has been helpful for me is taking an objective as possible accounting of positive and negative contributions to the relationship, with what is being done to address anything seriously negative. It's a good reference when I'm feeling emotionally overwhelmed or am mentally beating myself or my wife up, which is never helpful.