I would be really dissappointed because he has been living a lie and he/she made us live that lie too. But a part of me would understand because if it's hard for me to Get out of tje closet for him/her was a loooot harder
I would be scared to be honest. It would mean that their whole life has been a lie, and the other parent would be put in misery, and I don't think I could take that.