Progress but hope-less with young family

Hi - i decided to sign up here because it's Christmas and I'm at a loss. We have two young children (about to be 3 and 5) and it seems like all the strategies, and truth be told all of my life, now revolves around my partner (ADHD) and his needs. I just can't see how this works with children -- years before the diagnosis I told him that I was getting emotionally drained and wouldn't be able to keep going. And just like the book describes, I couldn't. I got really sick, I got depressed, I was angry and all the while trying to be the consistent (in all ways) parent to our children. I finally discovered that he might fit this diagnosis and thank god he was very accepting, got diagnosed, medicated and is finally, a year later, connected to a therapist he likes to and we have a couples therapist we both like. But I tried to cancel Christmas. It all felt so pretend so fake -- we have no sense of our finances, careers are shaky (his because he's discovered why he hates work so much and resigned, and mine because I started working part time in order to run the household and recover my health) and he wanted to leave it all to the last minute. Didn't want to take about traditions or values or other important things that children need and deserve.
I feel like all we do is have conversations to resolve conflict (specifically about his outbursts), fight in front of the kids, then I just keep trying to keep things together for them, and then I recover myself in order to do it all again that night or, at best, the next morning. As a part of our cycles, he'll pull up his socks and does amazing for a week or two, and I just relax because I deserve it too, then burns out and I'm on the marathon again. 
 There is nothing left in me to enjoy celebrating the season, we are cut off from friends, and all the normal ADHD marriage challenges PLUS the unique (right??) layer of challenges of trying to raise children who I hope to god will somehow grow to be somewhat well adjusted.
I don't know if this is the right place, it seems that most here don't have young kids. I need to be understood, and in need some serious help for my children's sake. I don't want to leave him, I love him and he's committed to working on things. He's a generous loving and fun human being. He's terrifically smart and he loves me. I need help. He keeps bringing up leaving for my and the children's sake. Help. Please.