Boyfriend spends time with his ex.

I'm a 24-year-old woman, and I rekindled my relationship with my boyfriend, who is 25, in July. We used to date in high school. When we got back together, I was aware that he still maintained some friendship with his ex due to shared responsibilities over their pets. I initially thought they only interacted when it was necessary for the animals. His ex has been in a serious relationship with someone else for over a year now. At first, my boyfriend wouldn’t tell me in advance when he was meeting up with her; he would let me know afterward to avoid upsetting me. However, I eventually asked him to inform me beforehand so I could gauge my reaction, and today he did just that. I trust him, but I still feel uneasy. I learned that she reacted emotionally when she found out he was dating me again, and he mentioned that she doesn’t like me. This is partly because I was involved with him while they were just starting to talk seven years ago, although I was unaware of that at the time. I’m feeling conflicted—I want to ask him a lot of questions to alleviate my concerns, but I also trust him. Having been cheated on before adds to my anxiety. I’d appreciate any advice or thoughts on this situation. Thank you!