i need advice

last summer my best friend and i started hooking up after i recently had a break up. it became really messy and in the end he was only using me for sex but i cares too much and still stuck around. after a while shit was just rough so we stopped and he replaced me with this other girl after he ghosted me. it hurt my feelings really badly and for months i was incredibly depressed. he sexually assaulted me and used me and then ditched me and i was heartbroken. long story short the girl he had replaced me with reached out to me a couple months ago and told me i was right about the stuff i told her and that he’s awful and that they’ve broken up. we became good friends and we hung out and talked often and i told her a lot of the personal things that happened between that boy and i, and it was really hard for me to talk about but she went thru a similar thing so i thought it was ok. a couple days ago she asked me if i would be mad if she talked to him and i told her i wouldn’t be mad i just don’t get why she would want to talk to him. she did anyway but i didn’t care all that much until i found out he invited her to his football game to watch it with his mother. she didn’t even tell me, i just saw her there with his mother talking to him. it made me feel so sad. i thought we were becoming good friends and i’m honestly really hurt that she would want to give him a second chance even after all of the shit i told her about. am i over reacting??