Divorce leads to the need to rebuild relationships with relatives, including grandparents. And it is very important that between the two families that take part in raising a child – the family of the mother and the family of the father – agreements on fundamental issues should be reached.
Quite often, in a divorce situation, the grandmothers take the side of their child – a divorced husband or wife. In this case, children can listen to very unflattering reviews about their parents. What the former mother-in-law says about you in your absence of nastiness may be evidence of her resentment for her son.
But when these unpleasant reviews are heard by your children, they are experiencing what has been called “conflict of loyalty” in psychology. On the one hand, a small child cannot oppose anything to the negative statements he hears from his grandmother; on the other hand, without reacting to these words, he feels guilty before his mother.
It is very clear your desire to change the situation. Here it is important to separate the relationship between you and the former mother-in-law and the relationship between your children and their grandmother. It is advisable to discuss the situation that worries you with your ex-husband and, possibly, to talk with his mother after that.
It is important that the former mother-in-law hear from both of you that you greatly appreciate her concern for her grandchildren, but insist that she discuss all her claims directly with you or with her son, but not with the children. It seems that you and your ex-husband have experience in working out joint decisions after a divorce: you have agreed on the frequency of visits, about where the children will spend time with their dad.
Perhaps this experience will help discuss the current situation and find the best way to convey to your former mother-in-law your vision of the situation.