My wife won’t let my parents babysit?

I would never have let my mother in law provide child care for either of my children when they were infants. There are a lot of very good reasons for that, and my husband absolutely agreed with that. Until you understand the true reasons why she doesn’t want your mom as a childcare provider, you won’t have the answer. Is your mother older, does she have health issues or mobility issues that would impact her ability to keep up with a small child? Does she engage in behaviors that might be undesirable (like smoking) or does she think that as grandma she can spoil the child and ignore your wife’s feelings or directions about things? Some grandparents feel it’s their right to spoil the grandchild, so don’t want to follow the established eating or sleeping schedule, or other rules the parents have made. I don’t know your specific situation, but I guarantee there is something else behind this.

Clearly, there is something regarding your 

mom that your wife isn't being honest about. 

Until you can sort THAT out, you will likely not 

past this issue.