For your children, you're definitely doing the right thing by hanging in there. For you, not necessarily. It's unfortunate that we can't have it all! Your children's happiness is most important, so please don't rock the boat.
I agree that this is a personality conflict between you and your husband, and has very little to do with the age difference. I was involved a long time ago with a guy who was 18 years older than me. He lost his job, and all he wanted to do was sit around and watch T.V. It was maddening, to say the least. In retrospect, I'm sure he was depressed (and your husband may be also). However, later on I dated a guy who was older (but the age difference was only 10 years), and he liked to do things with me all the time.
If your husband has always been this way - moody, difficult, etc., then I doubt he's going to change any time soon. If you decide to stay and put up with it, try to put the best face you can on all of it, and ignore his surliness. Take it day by day, and realize that you're doing the best you can for your kids. It's one of those "if life hands you lemons, make lemonade" ideas.
And if you leave, make sure you prepare financially first, so you're not left with nothing. Also, please don't date until your children are adults. Just my two cents.
