I have known a few people in my life whose "attractions changed". Not because of being transgender and not because of hormone therapy. They just "up and changed" at some point. A friend of mine's wife left him for a woman after twenty years of marriage and two children. A lady I worked with was a lesbian with a female "partner" yet she had been married to a man and had some children.
Society tells us to find someone of the opposite sex to love, but sometimes this doesn't work out or we just happen to fall in love with someone of our same sex.
