Throw truth darts. What did you really say to your niece? What could be construed as controlling? Your wife is projecting some, she is controlling you. Your STBX is still filling in the blanks (mindreading.) She's playing the victim here, remind her she has a choice that she can talk to whoever she wants.
M22,H45,W45 S21/18D12 Retain faith that you will prevail in the end, regardless of the difficulties and at the same time confront the most brutal facts of your current reality, whatever they might be.