Totally understand the need for validation from your MIL. She probably does internally but has a hard time not fully supporting her daughter. Like she does not want you to be a good thing your W is leaving.
You know the truth and you must rely upon that. If she had a better or worse opinion of you, what does that matter in the end? People think what they want and the only thing you can do is worry about how you react to it. Let it drag you down or brush it off.
It's only important on how you can rest your head on your pillow every night. Who is Jim and how does he live his life?
From what I've seen on here, Jim's a great father, husband and man who wants to do right for his family. Just my 2 cents.
All the best.
Me 42, Wife 39; Married 16; Together 17; Kids: D13, S10 Wife asks for Divorce: 03/19/13 Reconcile: 07/07/13 Round 2 Starts: 02/19/17 Apartment Life: 04/21/17 PA Confirmed: 05/23/17