What could you do to fix this up:
(note that since you did not give a lot of details,this will have some variation)
Speak to your mother when your wife is not there and say:
ma, I love you very much, but I am sure you want me to be happily married. Do you? she will say yes.
Do you agree that to be a good husband, I must defend, support (emotionally), and be loyal to my wife at all times? Do you agree that if someone disagrees with my wife, I should stick up for her and defend her needs and feelings over others’? she will probably say yes
Okay, so we both agree, so I feel that when you are insulted that my wife does not call you or… please just think about the fact that you are expecting from me to side with you, but you just said that you want me to have a good marriage and be loyal to my wife. However, you are not putting that into practice because I love my wife and love you, but you are putting me in between you and my wife.
Please accept my wife how she is. She DOES COME FOR SHABBOS. Are you happy she comes? she will say yes. So, just focus on the positive things my wife does, and it is not fair to my wife to compare her to her other dils; my wife is different.
Ma, I love you, but I am begging you that at least for Me, your son, try not to be insulted so that I am not put in the middle.