How To Treat Spouse?

In just the last few days I have come to realize that my spouse suffers from ADHD.  Having been with him for a very long time, so many things make sense now.  This situation has caused so much trouble and anger on my part.  He is frustrated and doesn't understand me either.

Mostly I just don't know how to treat him at this point.  He does not believe he has a problem, and I really can't imagine that he ever will.  I feel like being nice to him is rewarding him for treating me badly and not taking my concerns seriously.  However, all I want is to get along and be close.  And I think that if he is ever going to admit to anything it is more likely to happen if he feels loved by me.

Opinions, please.  I am the one who always does the apologizing and agonizing over everything, and this situation is killing me.