Thank you for your contribution.Will try to share my thoughts.
You've mentioned above you chatted about the FMF scenario. Well, does it still actually for you exactly? Good if not. But it could be possible she still remembers this aspect and has a “he will cheat me if I’ll cheat him” trigger active in that case. And this fact makes her feel scared of your marriage. Have you ever made her more confident and sure you are not interested in any other female?
I’m not an expert. Just sharing thoroughs as I said above.
By what she said and what I feel, it doesn't seem the case here. She has never put the fmf - mfm matter in a sense that "if this then that".