Venting over a cookie 🍪

Yesterday I picked up my kids from their fathers mother. She comes out and tells me that one of the kids was upset because his “stepmother” made cookies with them and she let him take the big cookie he made but he thinks I’m going to throw it in the trash. He’s right. I would throw it in the trash because I don’t want her involved with my kids like that. When they’re with me, I don’t want reminders of her. Why would I? I went through a lot with our breakup and honestly it’s her fault. I had to get into therapy just to not kill myself or both of them. It just really irritates me that their gma is trying involve herself and tryna make me keep a dumb cookie baked by a homewrecking bitch. She tells me it’s been 7 years and he’s now married so she doesn’t understand the problem. I don’t expect her to understand and why she thinks she can discuss it with me idk 🤷‍♂️. And idgaf that he’s married. It means NOTHING to me. Is it supposed to make me happy that he has moved on with his life and I’m stuck seeing him live out his life in happiness knowing that he dumped me for a woman old enough to actually be his mother? We had kids together but he leaves me for a woman who can’t have kids but she’s now got my kids to play mommy to half the week. SO PISSED OFF RIGHT NOW 😡.