How do I understand the root of my thoughts without engaging in rumination? Anyone have advice?

Honestly, medication really helps me not ruminate and just move on with my life. Right now the thoughts are still there all the time but I can still enjoy my life. Starting therapy with nocd in October to have a better understanding of relationships. I love the girl I am with and really enjoy my time with her and want to continue being with her so that’s what I’m gonna do. Hopefully therapy will let me get a handle on decreasing the thoughts.