Dear Prudence,
I’m tired of my boyfriend’s ex-wife coming between us. She is the mother of his child, and he evades setting boundaries with her for the safety of his son. She is unstable, and oscillates between nostalgic reminiscing and flirty texts, to sending inappropriate and negative remarks about my relationship with him. They text every day because they have to coordinate their parenting schedules, but depending on what mood she is in they are either old chums or she is completely souring our night and manipulating him into ruining our plans. When I (childless and never married) bring up my concerns, he tells me it’s none of my business how and when he talks to her, and that he needs to appease her because it’s what’s best for his child. How do I ask him to set boundaries without blowing up our relationship, and how do I not let her get under my skin?
— Sloppy Seconds