My (27M) GF (25F) talks so much about her exes. Why does this bother me?

My girlfriend was in a very dysfunctional relationship with her immediate ex. He was apparently very emotionally detached, and put her through a really traumatic experience. She has been working through it with a therapist. Lately she uncovered why she was attracted to him in the first place. Apparently they’re both ENTJ personality types, and she explained it was drive and ambition that attracted her. His alpha male qualities both in and out of the bedroom have been the discussion of many a conversations. But it was the same traits that also seems to have caused conflict. I listen and try to be supportive, though at times I internalize a lot of details mentioned and feel relegated to something inferior. Lately her ex before that has been calling from various phone numbers. They usually have a brief conversation and then she blocks him. He would also send messages of how he misses her, and feels bad for whatever he put her through. Recently she confided in me that they both have a shared traumatic experience, and on their last call they discussed it, and she wants to help him resolve some of his traumas and understand some of hers. Listen, I know I have my insecurities, but it doesn’t sit easy with me how often these people are mentioned, but also opening this line of communication. As for our relationship, affection and intimacy has dwindled. Anytime I gear up to discuss some of my thoughts, I’m told that I’m making this all about me. Maybe I am, so I bury this feeling, though it makes me sick. How should I proceed?