It's all about control combined with old patterns of behavior.
   The mother has more control over him. You have some control over
   him, but the mother is more powerful. Now, you can try to snatch
   him away from his mother and family and have him all for you and
   your kids, but either it won't work, or he'll become a hollow
   shell of a man. He loves his mama. In fact, I'd say its such a
   BIG part of his personality, that it'll always be there
   somewhat, whatever you do. Now 1st off: She openly badmouths
   you. But, think about it, you are badmouthing her on the
   Internet. That's open as well. You HAVE to accept that you and
   the mother in law are doing the same thing, perhaps in different
   ways. You have to sit with HER and talk. Take a relaxation pill
   beforehand, take her out to dinner, just you and her, and talk
   about it. She'll probably launch more hurtful things more
   quickly simply because the older women are, the more they know
   how to hurt you very quickly. It's a finely honed skill. Ignore
   the "remarks" and continue with the dinner. You can explain to
   her your feelings and that you want a healthy relationship with
   HER as well as with him. Ask her what SHE things would be a good
   solution. And even if her solutions seem weird to you, try them.
   Whether or not they work, at least you'll win brownie points. If
   you have brownie points with her, you will find her releasing
   him to you more. And also, help your hubby grow a set with
   regards to his mother. Tell him it hurts you when she talks
   about you and apologize for all of times you talked about her.
   (even if you don't feel particularly sorry). In the end, to get
   what you want, swallowing your pride and seeing the other
   parties involved as co-workers rather than mortal enemies, will
   be the greatest help of all.