Not good enough to stay, not bad enough to leave

I've spent hours reading posts on  this forum, like everyone else, your stories of ADD H, could be mine. Just recently realised that ADD is what is going on with H, after our son was diagnosed a year ago. Could never explain H's behaviours, always knew something was different but due to his being a rather avoidant and passive person who doesn't have the anger issues (well external anyway, have since realised he has successfully internalised it into passive aggression), but soon after marriage everything went downhill. Have begged him to get help, promises and no action is always the result. Every few months I find myself saying I can't do this for the rest of my life, but I see no way out.... Financially we're at rock bottom, 2 kids both with their own issues, and H is a very good man who "tries" very hard, but seems to never get it right. I've felt lonely, unfulfilled, anxious for 2 decades. It would crush him to lose this marriage as he is totally dependent on me emotionally and for keeping his life together, and I could never break up the family for what feels like my own selfishness. But, I've lived a completely empty and shallow life because I've spent so much time, money and attention on managing him and the fallout. I fantasise about having a man who can take the tiniest bit care of me, of not wearing the pants and being the driver 99% of the time. Sometimes I wonder if it would be the worst thing to quietly find someone that just from time to time can give me that so that I can stay the course. Its completely not the way I was raised, and I'm shocked at myself for even thinking this, but I can't see a way out and I'm tired of dying on the inside and being exhausted on the outside. I just cannot see a way out that wouldn't do so much harm to everyone, just so that I can feel a little fulfilled. Does anyone have these kinds of thoughts? I used to be a very romantic, fun person, loved planning surprise things, finding the perfect gift for H, sensual and adventurous, and now im just exhausted and aloof with him due to all the disappointments. I want to be myself again, and worry that the kids are not seeing what a healthy, balanced and fulfilling marriage should be. But I cannot see a way out, and I cannot stay like this and betray myself much longer - such a sad sad situation!