I can only express my personal story.
I came out to my wife after 14 years of marriage. She was extremely upset.
The truth is I don't understand it either. I know that some research suggest it is a variation in human development.
My wife and I went into therapy for many years. In that time, I learned that my childhood was not as normal as I had thought. There was physical and emotional abuse and neglect. Later, I learned that my step father sexually abused my siblings and me.
Research shows that childhood trauma, is also a factor. In addition to gender dysphoria, I was diagnosed with PTSD and Borderline Personality d/o.
I was always an angry person, prone to violence. This was not only due to my childhood, but suppressing and denying the feelings of femininity and wanting to be a female. Having that all bottled up inside, creates pressure, anger and resentment.
I have been married 34 years this month. Our relationship has evolved a bit. I am not transitioning and am not fully out, but she supports me. I take her lead with my transition, if it is to occur at all. She recognizes the struggle and is working on it. It's like getting into a hot tub, you need to go slowly in order to feel comfortable.
What is most important to me is my wife and family. Perhaps because mine was so chaotic and destructive. Keeping my marriage together and living is far more important to me that appearing to be a woman, but I also need to be free.
This is how she and I do it. Mutual respect for one another's needs.