You should seek legal advice about having your son more. I know you MIL probably has a lot of influence but this is between you and your wife.
If you would put a recap of your situation in your signature line it's helpful for others reading. You'll see My Stuff under the banner above, click it then select My Profile from the dropdown. Almost to the bottom you'll see signature. Thanks
Me 57/H 58 M36 S 2.5yrs R 12/13
Let me give up the need to know why things happen as they do. I will never know and constant wondering is constant suffering. Caroline Myss