I am stuck with all the real parental responsibilities
I know this seems tough, but try and look on it as a privilege. You are the real parent: anyone can do what your h is doing.
It may seem hard on you, but who would you really rather be? If you can look on it as a gift, it will help, truly. Mental attitude is so important. There are some great posters here with young children, who make their lives with their kids as much fun as possible, like Lissie and Shades.
I try and do the same with my older kids - we do fantastic stuff together, and are storing up memories of this time that are positive.
You can make it, with a better r with your kids than ever. An experienced friend told me that, right after the bomb, and she was so right.