Feeling lonely and hopeless!

I have been lurking on this website for months and have read more than one post I could have written myself.  I've been married to an ADD husband for 17 yrs.  Things have deteriorated greatly in the past few years.  He is a good provider and we have no financial problems relating to his ADD.  But his attention to our relationship is 0.  We have two boys, 15 and 10.  The 15 yr old is ADD as well.  Hubby had a very dysfunctional upbringing and poor relationship with his mother.  I am now paying the price for that in our home.  I feel that he transfers much of his experience/resentment towards her onto me now that I am the mother figure in our household.  I don't even know where to start in describing our issues.  I am just very frustrated, lonely and hopeless.  We tried counseling a year or so ago and things improved greatly for the few months that we both went.  But life got in the way and he has not been back and shows no interest or even acknowledgement of the deterioration of our relationship.  I still go occasionally just to vent my frustrations and have someone validate the way I feel.  Our physical relationship is basically nothing and he seems not to even notice.  He never suggests a "date".  Any time that we spend one on one is at my suggestion.  He seems to be capable of showing everyone in his life but me empathy and compassion.  I basically feel invisible much of the time other than being the person who cooks, cleans and basically keeps the household running.  If I try to bring up a conversation about the state of our relationship he gets defensive and over exaggerates his contributions.  I feel much more like I have a roommate than a spouse.  We are both committed to our marriage and I know he is clueless as to how unhappy I am even though I have tried many times in the past to address our issues.  I feel like I am suffocating and do not know how to reach him.  He thinks I am mad at him all the time...I have tried to explain my frustrations but it always leads to an argument.  So, we are basically stuck in this surface relationship.  Due to the blasted economy of the last 3 yrs (he is a custom home builder) I try not to add stress bringing up relationship issues.  He is stressed out enough trying to find work and provide for our family.  In the meantime, I feel like we are moving further and further apart and I am at a loss as to how to improve the situation.