Exactly. That's my whole point.
Or not. Depends. Even if it does, maybe by that point, you are able to accept things you wouldn't have at the beginning of the relationship? In fact, this isn't a stretch in any way. As relationships grow, you find out things that you might not like, that if they had shown up early on, maybe it would have killed the relationship. But once you are in, you look at all those great things about the other person and those negatives can be overlooked?
How can anyone say that this wouldn't happen to them with a trans person?
Someone mentioned not being attracted to tattoos earlier in the thread. What would happen if you got to the sex part and discovered a tattoo on a spot that you couldn't otherwise see. Let's make it a really obnoxious tattoo with the person's ex's name even. Can you say now that it would be enough to make you want to end the relationship? It might, sure, but then again, by that point, maybe you can overlook that tattoo because of all the other attractive features of the person? How can anyone say for sure until you are in that position?