So tired of being at the bottom of my husband's list

My (suspected) ADD husband is so eager to impress and please everyone, and can charm himself out of (or into) any situation.  But when it comes to me, it feels like he doesn't care at all.  He has no interest in anything I say, and will actually walk away from me when I am in the middle of telling him something.  He has, on occasion even walked out of the house while I was in mid-sentence.  Today he actually closed the door of the room he was in, so I could not talk to him from the next room.  The one sure way of getting him to NOT do something, is having me ask him to do it - no matter how simple the task.

We are on vacation with our two young children, visiting an old friend of my husband's, who has moved to another country, and I feel like a tag-along - like I'm not even supposed to be here.  We spend every waking moment with his friend, and his friend's circle of friends.  I'm an introvert, and need quiet time to recharge - something my husband is well aware of - and I am exhausted by the constant interaction with people I hardly know.  (Not to mention the fact that my husband's friend is THE loudest man I've ever met!). I like these friends very much, I just didn't realize they'd expect us to spend every single moment with them.  And yes, I have expressed this to my husband.

Today, I was in bed all day, sick with food poisoning - and my husband somehow thought this would be a great day to finally entertain friends at the house.  They lingered over coffee as he made them breakfast, then offered everyone drinks when they dropped by after tennis - all the while laughing and conversing loudly, as I fought stomach and headache upstairs in bed.  When I told him I was upset at his lack of consideration, I could tell he was angry.  This is always the pattern:  he does something inconsiderate or thoughtless (sometimes even cruel), and when I express my upset over it he gets angry at me.  Because in his mind, he's done nothing wrong.

I have read and researched ADHD, and suspect that he does have it.  After some initial resistance, he is now beginning to accept this as a possibility.  I have recommended some of the books and websites I have read on the subject, but he can not be bothered to read them.  One book I brought with me, I left in his bathroom to skim (it's written in bite-sized chapters, half page each) but he wouldn't read it.  I then bookmarked the "chapters" I thought were relevant, but he laughed at me for doing that, and still would not read it.  I tried to read it aloud to him, but he couldn't be bothered to listen.  

I'm at my wits' end.  I have suffered so much mistreatment and neglect by him, and have searched for answers and solutions in my self, knowing that I can't change his behaviour, I can only change my own.  When I considered divorce a few years ago, I told myself I needed to do everything I could to save my marriage, so that if it did ultimately end in divorce, I could tell my children in all honesty, that I had done everything I could to try to make it work.  And I truly have.

I realized today when he would not read the book, that I have been trying so hard to get him to make an effort, but he just won't.  I have been trying so hard to be understanding.  I feel I have the insight, ability, and desire to comprehend how ADD creates certain patterns in his behaviour and in our relationship.  I accept my responsibility in these patterns.  I want to find out how to alter these negative patterns to improve our relationship.  But without him acknowledging the effects of ADD, we can't work on anything.  And I just continue to suffer - despite all the efforts I've made.  I'm feeling like I've waited a long time for a change that's not going to occur, and thinking it might be time to separate.