I recently ended a yearlong relationship. We parted amicably, though I don’t see us becoming friends anytime soon. He lived at my place, and when he moved out I decided to take the opportunity to move to a new apartment. While packing, I removed the waterproof cover that my ex had put on the mattress to protect against his profuse night sweats. To my surprise, dismay, and disgust, I discovered that the cover hadn’t been sufficient, and my mattress was covered with sweat stains on the top and mold on the bottom because the sweat had soaked all the way through. Is it reasonable to ask my ex to help pay to replace my mattress? It was nearly brand-new when he moved in, and now it’s ruined. I don’t want to be rude or petty, and I know his sweating problem is not his fault. But it’s not mine either, and I really can’t afford to replace the mattress on my own. What is the right thing to do here?