Rightly or wrongly, your ex resents you and wants to see you in the most negative light possible so she can justify her anger. She probably enjoys the feelings of superiority and seeks also to justify her possession of your children. She probably also seeks to project her personal happiness onto someone else and this only possible if you are a “bad” person. In other words, so she can say to herself: “It’s not my fault I’m unhappy; it’s his fault.”