Your MIL may have some underlying issues that have nothing to do with you such as mental illness, jealousy, or perhaps feelings of losing control over her son.

I find it really cruel that she was leading you to believe that your relationship with her was good while speaking poorly of you to others in the family. It must have felt like you were the last to know the truth.

I know how hard it is to amend yourself in order to gain acceptance from someone who has already made up their mind that they don't like you. You tried and she just didn't want to accept you.

I am glad you chose to just be yourself because that is the person your husband fell in love with and the person your child needs you to be.

Her behavior has nothing do to with you so much as it is a reflection on her...try and remember that and kill her with kindness. Treat her with respect and acceptance and be firm with what you find to be an overstepping of your boundaries.

Hang in there!