I want to learn and grow from my breakup but I don’t have a clear story.

My ex and I broke up early April and her reasoning at the time was because she was really stressed from school. I also asked when we were breaking up because I made it hard on her or unhappy and she said no. But when I went to her graduation cause my cousin goes there I believe I saw another guy there with her family and that same month she was matching bios. This was in early-late June. I decided to text her cause it didn’t make sense and she said it was because she was stressed from school and because she felt like we were too combative. She also said it wasn’t anyone’s fault. Then I find out that maybe because I was controlling? I don’t know what it is. If I was too controlling then I’m glad she broke things off. But to me I felt like I wasn’t. I did my best to always approach things calmly and I always said that it wasn’t because she did it just that I just wanted to be better informed about if she hanged out with guy friends or what she texted about with them or something like that. I should also mention that when we first met and dated she texted her ex behind my back and said bad stuff about me but I decided to give her another chance given that he was manipulative. What do you guys think? Was I in the wrong or no?