I don’t know whether any resources are available, but I can give you my tips. My boyfriend and I both have ADHD so it’s a bit easier for us to understand each other.
That’s the first thing, know yourself and your ADHD. Know your strengths and weaknesses and discuss them with your partner. Communication is everything.
For example: You may need to ask me to do something multiple times, because I am very forgetful. It’s not because I don’t care about you or because I don’t want to do it, it’s just because I simply forget.
Also, think about how you would like them to communicate with you. If you forgot something they asked you to do, what should they do? Simply ask again? Give a hint? Ask whether you remember? This is equally important because I think as people with ADHD we carry around a kind of guilt. Saying the wrong thing or using the wrong tone can make us feel judged and patronised.
You may experience emotional outbursts. Let them know that it’s not because of them, that you can’t help it and that they shouldn’t take it personally. You just need to get rid of emotions and they were the first person in sight. Again, ask yourself what they can do to help you. Should they leave you alone or do you need a cuddle? Maybe it’s different every time and they could simply ask whether they can do anything for you or what you need from them.
Also, apologising does not mean you were wrong. I think because of that guilt thing, again, we may feel reluctant to apologise because it implies we were wrong, but that’s not true. Instead of apologising for your behaviour, apologise for how it made them feel. Tell them you didn’t mean it, tell them why you did it, whichever applies.
When your mind wanders during a conversation with them and they notice and accuse you of not caring, you can say: I’m sorry for making you feel unheard (address their feelings), that wasn’t my intention. My mind just wanders sometimes and I can’t help it. Next time, I will try to let you know when I’ve lost you and I hope you won’t mind repeating it, because I do want to know.
It’s important to realise that some things are largely out of your control, like forgetfulness and not being able to pay attention in conversation. The key is to try to find little solutions together, which all starts with understanding and acceptance. They shouldn’t mind repeating themselves at all if they understand why that is necessary sometimes. They may even suggest things that may help.
Also, keep a sense of humour. If you can laugh at difficulties together, they don’t seem so difficult anymore.
It sounds like a lot of work, but trust me, if it’s the right person these things should be much easier than they sound. They will gladly accept your weaknesses because they love your strengths. Over time, you will know each other very well and these things become second nature. But in the beginning, you will need to communicate these things, no matter how difficult that can be.