Similar to what others have said - I also refer to my husband as "high functioning" because he is successful for his age, makes good money and he has never had a DUI, etc. That doesn't mean he hasn't driven drunk, however. Or that he hasn't had an accident because he "fell asleep" at the wheel after drinking.
But, my husband does not function well in relationships. We no longer live in our home state, but when we did he rarely saw his friends, and there were invariable reasons why (they had girlfriends, got married and their wives always wanted to hang out with them, etc.). In our new state, he has met no friends in the past almost 11 months. None. He says the guys he works with are all older and have families. Maybe this is true. Anyhow, when he does see his friends they typically drink together.
We are in our early 30's, so being "in the middle of it' it is hard for me to see the progression. But I do find it odd that he doesn't ever really converse with me, keeps to himself even in our apartment, and seems to want little to do with me (even sexually).
Hang in there and please keep us updated. I will say this - Al Anon has saved my life.