Penny, Hang in there and remember that you are not worthless. You are "carrying the freight" for your whole family and that must be really difficult. Yet your efforts and dedication do have a great deal of value -- more than you may percieve at times. We all have to learn that no matter how good or how bad our relationship with our spouse is, one's value as a human being, as a child of God, can not be determined by another.
I am sorry I have no "advice." If I did, it would be like the blind leading the blind.
I would suggest to find ways to treat yourself, and to find joy in the moment wherever possible. I know it sounds easier than it is, and some days are better than others, but remember you are worthy!
Me: Male, 41 Spouse: 40 Married since: 1994 Children: 2