Tired of the Roller Coaster.....losing hope.

I am new to this site, and feel grateful to have found it.  I think right now I either need to be "talked off the bridge" leading to divorce or pushed off completely just to finally have some relief.  My marriage is in big trouble and it has been for quite some time.  At this point, there is essentially no communication between us except for the defensive, argumentative variety (if that is even "communicating").  Most days, it's better if we just ignore each other, but this is no way to live either.  I take full responsibility for not always being the most loving, kind wife.   I have said many things I wish I could take back.  But I don't feel that I have ever built a wall around myself that won't let my husband in....ADD and a myriad of other issues seem to have built that wall around my husband, however. He is essentially emotionally and physically completely unavailable to me.  His wall seems fortified.....The hardest part of all of this is that we have a young daughter (6).   Thankfully, he is a wonderful father, although lately seems to lose patience and become highly irritable with her very quickly.  But none of this is good for her....Parents who don't civilly interact with each other, parents who don't really interact at all, a family unit that is not a family unit.  I don't remember the last time we all did a single activity together, and if we did, we didn't enjoy it or it wound up ending in emotional firestorm.  Suffice it to say, I am completely fried.