I was dating a person who was incredibly feminine, in every aspect, but claimed to identify as they / them. I made sure to always refer to them in a gender neutral way, but I made a mistake twice, and really beat myself up about it. And they let me beat myself up. And then I learned they actually identified as she / them, but really amped up the they / them just just dating profiles. Everyone in their life referred to them as she / her and they were fine about it, but they absolutely let me feel terrible whenever I referred to them as she / her, and called me our hard both times, despite my obvious attempts to respect their gender identity. They also gave me a lot of shit for a bunch of other things, which blew my mind because I've always been such an ally for progressive causes.
I'm glad I'm no longer speaking to them.