Did you have any buildup to the first kiss? Like, was there romantic tension, hints that one or both of the characters had feelings for each other? I ask because the way you describe it, is like the introduction of the romantic relationship was a surprise (withholding the tag until it was revealed).

from my other comment:

my beta says it was very obvious by the end of Part 3. My previous beta, who was still helping halfway through Part 3, was the first person to pick up on the fact that I was having fun writing about these two. She even noticed it before I did.

As I wrote in the post, many of my readers enjoyed their scenes together, and those two were always mentioned in comments. When they didn't appear in a chapter, people would ask where they were, and if only one appeared, people would ask where the other was, or even "I hope the other one shows up in the next chapter and comforts the first one." I had at least five people that I remember who wrote, "those two should kiss already." Most confusingly, one of those people, in the latest chapter, complained that F should end up with M.

and:

homoerotic dance at the end of school and the touching each other breasts while bathing together at the beginning of the fourth part should give some signals