I can not imagine how I would feel in your shoes @Lanahope . It must be so hard to hold it together. It sounds like you have the weight of the world on your shoulders, and it seems so unfair that you are burdened by your mother, and betrayed by your husband. I would be SO angry to find out about three affairs, and couldn't trust again if it had been broken so badly, with signs of these betrayals still happening.
It is great that your kids bring you happiness! I think your happiness is important FOR the kids, too! I hope you find a way to get what you need in this situation. I hope you can have happiness and peace with your children.
I can understand wanting to get away so badly, while not wanting to lose what you have.