Feeling disheartened

My husband has been diagnosed as ADHD and has been on meds for about a year. The medication has calmed his anger and frustration but he is still completely detached. When he is home it's as if he isn't even here...he doesn't respond to his name being called, doesn't engage in conversation...he's somewhere else mentally 98% of the time. After all the reading I have done I am realizing that this behavior most likely will never change. I feel sad and lonely, and am really worried that our marriage won't survive this. When I got a married, I wanted to spend my life with my friend and partner. But I don't see that emotional and mental connection ever happening between us. I feel that it is alot to ask for me to give up having that type of marriage. Right now I feel like I just have roommate and I sit waiting for the 2% of the time that he will actually interact with me. I am at a loss as what to do...