I suspect my partner has ADHD, how to speak to him about it?

We are in 2,5 years long relationship and we've been living together for a year. I've suspected for a few months now, that my partner might have ADHD. I've read so many different articles and the way he behaves and how he makes me feel is very similar to described behaviours. A few months ago I did a little "self-diagnosed-ADHD- quiz" while he was playing his video games, I was asking him different questions and all his answers proved that he might have it. He got furious that I am trying to diagnose him. I assume he would feel very ashamed to admit it if I was right. I love him very much and I want to do everything I can to help us be together and to be happy. I feel very lonely, unseen and exhausted as I do all the home tasks by myself. It really feels like a parent-child relationship. We argued a couple of days ago and he left me to spend some time with his family. I would like to have an honest conversation with him when he returns. I just don't know how I can talk to him about it so he doesn't get furious or say hurtful things. There is a chance I might be totally wrong, but I am afraid I am not. I feel that if he at least listened to me and read the same articles, maybe he would realise that we can change it. He blames me for being sad and depressed and annoying and he just leaves me on my own. And every time I try to confront him, he just gets angry and either breaks up or just leave me in the room. I just want us to be the way we were at the start. How would you speak to your partner about it?