How can I (f21) let this thing go about my ex(m22)?

Hi, so my ex and I dated for a little more than a year and it ended because both of us were toxic but I was the Main initiator of the issues. So during our end days it was an on and off kind of situations. I said no matter what we do we are not committed rn and he had a flat at that time. My friend and I needed a place to stay as we had an event and he offered it to us and I told him that we are still friends only and he can’t stay with my friend and I to which he agreed. My friend told me that she won’t stay as she wanted to go Back to her place and I did not want to spend the night with my bf at that time.
I had hinge during our break and met a guy from there and we hooked up. The next day I told him wtv happened and he was not ready to believe me but he eventually did when he saw the chats. This is how it basically ended.
I had then drunk called or texted him sometimes and basically in may we hooked up again. He told this thing to a classmate of his. Now this girl has been an everlasting problem in our relationship. He says he has no feelings for her but he needs her help as they are In Same dept and everything. I have seen his chats and calls but I have never seen any signs of cheating. He’s always been like I don’t like her but have to talk to her because of wtv course or something.
But why he is telling her all this so comfortably as he always said that he doesn’t consider her a friend or anything. They work together only.
I dong feel for my ex now but we talked today and he told me that he told her about when we hooked up after the break up and I don’t get why can’t i let that girl go. I don’t have this many issues With his exes but I can’t let that girl go and I feel more irritated because I don’t really have this issue of being insecure regarding women.
Ik I have done my own share of bad things but I just want to know how to let that girl when it comes to my ex.

reddit.com
u/cherrcola03 — 8 hours ago
▲ 1 r/Breakupadvice+1 crossposts

How can i(21f) let this go regarding my ex(22m)

Hi, so my ex and I dated for a little more than a year and it ended because both of us were toxic but I was the Mai initiator of the issues. So during our end days it was an on and off kind of situations. I said no matter what we do we are not committed rn and he had a flat at that time. My friend and I needed a place to stay as we had an event and he offered it to us and I told him that we are still friends only and he can’t stay with my friend and I to which he agreed. My friend told me that she won’t stay as she wanted to go Back to her place and I did not want to spend the night with my bf at that time.
I had hinge during our break and met a guy from there and we hooked up. The next day I told him wtv happened and he was not ready to believe me but he eventually did when he saw the chats. This is how it basically ended.
I had then drunk called or texted him sometimes and basically in may we hooked up again. He told this thing to a classmate of his. Now this girl has been an everlasting problem in our relationship. He says he has no feelings for her but he needs her help as they are In Same dept and everything. I have seen his chats and calls but I have never seen any signs of cheating. He’s always been like I don’t like her but have to talk to her because of wtv course or something.
But why he is telling her all this so comfortably as he always said that he doesn’t consider her a friend or anything. They work together only.
I dong feel for my ex now but we talked today and he told me that he told her about when we hooked up after the break up and I don’t get why can’t i let that girl go. I don’t have this many issues With his exes but I can’t let that girl go and I feel more irritated because I don’t really have this issue of being insecure regarding women.
Ik I have done my own share of bad things but I just want to know how to let that girl when it comes to my ex.

reddit.com
u/cherrcola03 — 8 hours ago