Behaviour problem. Now biased for same!

My problem is related to my wife behavior. she is 28 now and married with me since June 2014. she have developed hatred for my family since marriage and now we stay away from family in different rented home since Feb 2016 when fights and cries were daily. now she is a bit better, but still whenever she and I have a talk in my family, we have a fight despite it being a very silly point just to be neglected. she use to be an aerobic performer and a sporty person before marriage, but now gained 30 kg weight. now she is a mother of 5 months old child delivered by Caesarean section in Jan 2017. most time she tries to keep her busy but on topic of mom dad and family she gets upset, and stop talking to me .. I try to explain her to neglect things but she continue to think and over think. she also start thinking that when she would go to her mom home, I would be pulled to their side in her absence. lot more things which I think is not intentional from her side , but she is now biased for same