Undoing a marriage adds a lot more complication than postponing/cancelling a wedding. You need and deserve time to really consider your boundaries and what is best for you. It is not at all selfish. You were just now told information that is pretty major and impacts your life. You were told this information at a time that was about planning your wedding! Granted it was before the wedding which is better than after. It was known that you happen to be heterosexual yet you were not clued in that your soon-to-be-spouse had a long term desire to be considered a woman, which it not compatible with a heterosexual woman’s sexuality.

Please please take the time you need to make decisions that work for you. Not just what is “kind” what is “loyal” but what works for you. You have every right to advocate for yourself and your future. The reality of the situation and the facts you now know may be ok for you and they may not. You deserve time to figure that out.

Also consider your personal boundaries. Should the truths you now know not be the whole story, what then? You very well could have the whole truth now but it can be good to consider what your limits and deal breaker truly are should you be surprised again. What are your personal boundaries? What changes are expected if you in all aspects of your relationship with this? What are you on board with truly and what are you not? You get to decide.

In my personal situation where were several escalations and several things I was not ok with but felt it would be “mean” to say no. So I really suggest thinking what your personal boundaries are and knowing your wants/desires/feelings are not less important.

So sorry you are going through this pain.