How Do I Tell My Parents That I Don't Want My Ex Sister in Law and Her Family to Stay in My House?

My parents used to let my x sister in law and her entire family use the house for a week every summer. Now whenever i see her, she always asks me how the house is coming along. She'll even text me on occasion to ask about it. Her husband was my brother's best friend whom she started cheating with. I sometimes feel like their taking advantage of him in his good fortune. How do i tell my parents that i don’t want them staying in my newly remodelled house? Givin em to the counaten to get their ugly, yellow, no good chitos off my property. Good reference.