Good job. My advice, go back and reread your old posts about what lurred H back in the first time. Keep it up, sometimes we get H back and we fall back in to our "old routines" and H gets comfortable again. It takes work, everyday work, just like a job, if there is one thing I have learned about my M it is that. I can't let it fall to the side and fall back in to our "old routine" b/c that didn't work the first time. I wake up every day and say, what can I do today to make him feel special, what can I do to be a good friend? and then I do it. And those actions have been reciprocated by H as well. I understand your frustration, and I think maybe H being home w/ no job doesn't help either, it gives him more free time.
I think maybe the OW is chasing him makes him feel needed in the sense, so he is "stringing" her along for that sake of a void he may be feeling. I don't know for sure. My advice would be take care of yourself first and reread what made him come back the first time. But then don't overdo it when he get comfortable again, it takes time, he will slowly break away from OW, you need to think of her as a ghost who doesn't exist. Act "as if" it doesn't bother you, you go on your own and find a job for YOU, don't wait for him. You can do it, you've done it before, just trust yourself.