Children from former marriages

I'm non-ADHD wife married to ADHD man with 2 previous marriages, 2 children from each (all adults now).  Being older we have no children from our marriage.  We've had all the usual ADHD problems around  chaos, time, chores, anger outbursts etc, and I can mostly deal with this stuff.  What really gets to me is that I'm the last priority after the 4 children,especially the first-born--this seems to be his primary relationship, and the person with whom he shares his feelings by email (what a bitch he's married to etc).  I just don't seem to count, except for keeping house and occasional sex (I'm not very enthusiastic any more). This is wearing me down so much, that I just feel miserable and depressed, and want to escape.  I just don't feel like I'm part of a couple at all, so what am I doing here?  I can't find any postings on the forum like this, so perhaps this situation is not related to ADHD.  Can anyone relate to this?