@ajddavid452 It will never happen, in the majority of cases at least.
After all a straight guy won't just be fine with his girl turning into a guy and vice versa.
He could be fine with a guy who turned into a girl if the dna and body structure changed too like in this manga, howerever irl such a thing is impossible and the closest thing to this is gender reassigment surgery and the number of straight men who date trans women is very low.
tldr: real life isn't a fairy tale.