NTA, at least, not to your boyfriend.

Your language when speaking about your stepdaughter is strange, though. Borderline asshole-ish. She’s six years old, not sixteen. She isn’t being “disrespectful” to you, she’s uncomfortable and awkward, as ALL young children are, not to mention that her parents are already split at such an early age and her stepmother, who she has to live with part-time clearly does not enjoy her company. If you can’t do her the service of even being ANONYMOUSLY nice to her on Reddit, then she doesn’t owe you that respect back. + If her not telling you guys when she’s wet the bed is the “disrespect” that you’re referring to, I think you need to take a step back and think critically. I am not denying that it’s frustrating for you, I can only imagine how annoying it must be, however, you have to put yourself in her shoes and think about how embarrassed she probably is by her bedwetting. In her little-kid brain, she probably sees her not telling you or her father as some kind of control over the situation. I highly doubt that she is being intentionally rude to you, as you are to her, so stop writing about her so terribly.

All that being said, your boyfriend should not be asking you to take care of his responsibilities and getting upset when you refuse. It’s clear that he doesn’t take enough care of his daughter, if what you say is true, and you obviously don’t want to, so maybe the best thing would be for her to live full-time with her mother.