A heteromosexual is a person who is
heterosexual or 'straight', but would still date the person if they came out as transgender, although they are not
necessarily attracted to men/women/enby people.
Someone who is heteromosexual may consider themselves straight, but will still love their partner the same way if they decided to transition.
Heteromosexuals are not sexually attracted to any other gender than their opposite, but will make exceptions for partners they are already with.
Not being a heteromosexual and leaving a partner because they are
transitioning is not wrong. It is your decision and it is likely a very tough and confusing situation anyway. You have no reason to feel bad about it.
Friend : I heard your partner came out as trans, are you going to leave them?
Lad : Nah, I'm a heteromosexual - I'll still date them even though they're trans.
Friend : So you don't have a problem with them
transitioning? But you aren't gay, right?
Lad : I'm straight, yes, but I've already fallen in love with them, and their
gender identity wouldn't change that.
Friend : Oh, cool. Now I can still write
fanfiction about you two.
Lad : Wait what-
