My ex-husband and I divorced five years ago after 12 years of marriage and three beautiful kids. We stayed civil, co-parented well, and life moved on — until his much-younger fiancée, Rachel, entered the picture. At first, I tried to be polite. But things quickly turned tense. She told my kids to call her “Mom,” went through their things, and insisted on being in charge — despite the kids clearly resenting it. But the real tipping point came when she stormed into my home one day and said,

“You need to change your last name. It’s weird we’ll have the same one when I marry Mark.” I was stunned. “You’re serious?” I asked. “Dead serious,” she said. “I want it changed before our wedding.” I kept calm and replied,