Feeling lost and struggling with changes in partners identity

Hi everyone.I've been met with a situation I never expected to deal with and this is the only place where people seem to have similar experiences to me.And really I just need some help and advice.I'm a trans woman and a lesbian which I've always conceived as an important part of my identity and how i experience relationships I'm in. My partner who has previously identified as trans feminine recently told me they were sure they were non binary and they felt their female identity no longer represented part of them.This is not something completely new but during our romantic relationship,they identified as such and I thought of them as a woman,particularily once we became very close.I was under the impression as they'd explained it this way that it was something they simply didn't feel safe expressing due to various reasons or they were genderfluid in some way.Now they say they don't feel its part of them anymore at all and it has completely fucked me up because the critical aspects of our relationship such as kink were with them in this feminine identity.I feel like I've lost someone I loved and desired deeply and I'm struggling with feeling the relationship is the same.I do love them so much and I want them to be okay and comfortable in their identity but I've found myself crying constantly and grieving what we had before.The last thing I want to do is hurt them but i feel like everything which I dreamed of/fantasized about and many parts of them I loved just aren't there anymore.They say that nothings changed and theyre still the same person but thats not the case for me.They're expecting me to just move on and provide support and replace personal effects with their old name on it but the idea breaks my heart.I know I'm an awful person for it but i can't fix that feeling.I can't help but be attracted by the parts of them that are feminine and want to be with a woman and I feel intensely horribly guilty about the whole thing.I'm scared maybe I manipulated them into being female when they weren't comfortable with it or something.I just exist and my heart hurts and there's nothing I can do to set it right because they're not that person anymore.I don't know what to do.Does anyone have any advice or just comfort?