How to broach the subject of adhd

I'm new here and really struggling. My husband and I have been together since high school and I love him very much. We have 2 kids and I genuinely want our marriage to survive. I have always thought that he was a bit different, and, over he past year I have come to realise that his symptoms match exaptly to those of ADHD. For the sake of our marriage I need to speak to him about it. He needs treatment as his untreated symptoms are causing huge problems in our marriage. I feel very down. How do I broach this subject with I'm?  He has no idea that I think this and won't take it well when and if I broach the subject with him. I just don't know what to do.