Am I the only one who didn't want them to have a threesome?

I don't really mind if it doesn't happen in the main story BUT I really would love something like Inkyoo's dream of them doing it ლ(´ڡ`ლ). Still at this point of the story it would change the whole plot since their relationship would go from super dedicated etc to open to some fun (which in some cases it's good and all but they are at the start + their previous situation wasn't that good)

I really don't get why people want it,it's ridiculous.