I can understand your feelings. I would like to ask a few questions, why didn't you approve of him playing golf, roller skating, and such? Was he ever "allowed" to do things he enjoyed? Just because you are married does not mean that you can no longer have a day to yourself. I see that you say he has no friends, that is either because all he ever did was go to work and come home or he is a bad person. I don't see you staying with a bad person for 28 years. I also don't see how you can say you are getting your life together if he is still supporting you financially. Until you are paying your bills your life isn't together. (I mean with the assistance of child support)
You also mention his meddling sisters, If the shoe was on the foot and you were the one that was unhappy and wanted to leave him don't you think your family would tell you to do what makes you happy? I know all 5 of my sisters would be jumping up and down screaming and throwing a fit.
You also call your husband selfish. Why should you stay in a marriage that you aren't happy in. If you aren't happy then no one else will be happy either. I am sure you have heard the saying that if Mama ain't happy ain't nobody happy? That applies to daddy too.
I apologize if this sounds like a personal attack against you. I promise you it is not. I am simply just giving you a few things to think about that it doesn't seem like you have thought about. (I am telling you stuff that a good friend should be telling you and since I am a friend to everyone I am telling you.)
Good Luck!