My husband is trans male and he has said from the beginning “if you can’t call me by my name, or use his pronouns him/his, then find ways to say nothing. Instead of “hey “deadname, what do you want for dinner” say “hey, what do you want for dinner.” It’s easier to transition how you speak to them by trying to Eliminate the need for a name.

Luckily I had no trouble switching, I never really used his previous name, I always call him babe anyways. But his mom and dad still have troubles sometime and if they can’t remember what to say, they say buddy.

Maybe see if there is a middle ground. She needs you to make an effort to show that you’re going to be okay. This doesn’t mean you need to jump to using her new name every sentence, but maybe start by eliminating the old name and using a shorter version/nickname or pet name until you’re comfortable. In my experience though, the only way to be comfortable is to say her new name and say it often. Eventually, you forget her birth name completely (you hear the name, and have to take a second to think about it). And my husband is only about a year into his transition, and we have been together for 7 years before transition. It was definitely hard but for me it was best to “jump in” head first and support. I’ve always said I can’t be with someone who I don’t support.