(input from hubby familiar with both parties)
The dynamic between you and your mother has always resembled the following....
Your role...you are polite to your mother, the relationship with your mother is and always has been important to you, you enjoy being around her in small doses especially when sharing a few glasses of wine, you have had some common interests/hobbies over the years that you enjoy, you never argue with her, you are never disrespectful of her.
Your mothers role...she comes to you so that you can be a sounding board for every problem she has, she asks for your help and support, then after you have freely given of yourself and her problems are solved to her liking, she starts in on you and the religion like you are a 12 year old.child. She works herself into a lather and you become the sole focus of her JW rants. You sit there and say nothing. When her toungue lashing is through, you politely excuse yourself.
You deal with her abuse by saying nothing to her, internalizing it, coming home, getting angry, then getting depressed.
The simple answer is that you need to lay new ground rules with your mother. You have never stood up to her.
Are you a passive, mamsy pamsy person by nature? Absolutely not ! You are not afraid of taking on anyone, anywhere, ever!
With your mother however you absoluely freeze... every time for 47 years!