SO with ADD

Madi
My boyfriend has ADD, he's been diagnosed since he was young. Recently he's started a new medication to help him focus, but it's causing him to experience some erectile dysfunction. He has had this issue before with ADD medication but we weren't together. If he can't get fully hard he's angry with himself. I do reassure him that I'm not angry or ever going to leave him over it. Any advice on how I can help him deal with it better?