God i think all mother in laws should have restraining orders so they can only come over once a month. Mine is exactly the same and coz its his mum i can only say so much before he goes oi pack it in its my mum.
Recently i had to give up some extra work that i had been doing for work (id been taking data entry home to earn some extra cash) but i was just finding it too much with two kids another on the way, work, studying (im studying to be an accountant) looking after the house and running round after hubby. All she could say when i told her was to look down her nose and say Oh..if thats what you want to do. Poor steve (hubby) will just have to do more hours i suppose.
You need to say to your husband, tough! This is for your family now and that comes before his mum. Shes had her turn playing mum when he was growing up, its his turn to do it with his family now and enjoy it. Not being held back by her.