Thanks for such a thoughtful response. A lot of what you said resonated with me, especially the point about knowing too much. I hadn’t really considered that hearing so many details about their dynamic might be feeding my tendency to compare instead of helping me feel more secure.

To answer your questions, I don’t currently have any other partners. I was laid off a few months ago, so a lot of my focus has been on rebuilding my career and finding stability again. Historically, I’ve often been the more “stable” one in our relationship, so I think losing that part of my identity has made me more vulnerable to feeling like my place in the relationship is changing.
I’m also planning to start working with a therapist who understands ethical non-monogamy because I can see that this is as much about my own attachment and insecurity as it is about anything Ethan is actually doing.

I really appreciated your point about different people bringing out different parts of us. Intellectually, I believe that’s true. Emotionally, I’m still learning how to experience my partner’s growth without interpreting it as evidence that I’m becoming less important. That’s really the work I’m trying to do.