Is this worth it?

i married my wife. we were so in love. she told me i was the love of her life. as time went on i could see that the pressures of marriage were making her fragile. her mother was a controlling ***** who's advice was always tainted with her leaving me. that's how she grew up. her mother was a total *** that didn't want to see her daughter happy all the while telling her she loved her in between telling her she was a piece of ****. i heard it. my wife got weak during a down time in our marriage, she had an affair, she then listened to her idiot of a mother and instead of a happy life she's now divorcing me. i know why she's messed up. she just wants someone to love her. her mother messed her up and continues to by saying "i love you honey but you're so screwed up". I want to fight for her, should i or is it a lost cause because apparently she can't get her mother out of her life.