They knew something that I didn't: that my gender dysphoria wasn't my fault and I needed to examine it up close. It took several more years to get to a place where I could feel comfortable with who I was.
I used to be in a marriage that I thought would only work if I “fixed” myself. In the process I learnt that there were bigger issues present and my being trans was a ruse. No one deserves to be blind sided with news that wasn't disclosed from the outset but if you are upfront from the start the partner cannot plead ignorance. There is a plethora of information available to them online about what being transgender means.
If that person sees it as perversion or mental illness then you are at an impasse because conversion therapy isn't the solution.
I truly and honestly believe that true love can accommodate a transgender partner most especially if a full transition is not a desired goal. Therefore to be held hostage by an intransigent spouse who thinks you are disturbed is not a good recipe for a healthy and sustainable future.
I wouldn't dare presume to advise anyone on their relationship but would only counsel you examine yours closely to make sure it's not a one way street.