I realized some people didn't understand this the same way I did. From my point of view, it's not that he fell in love with the one who was locking him down, but it's that they weren't on the same "frequency". Basically both of them wanted love, but the seme tried tu subjugate him and he didn't know how to explain that if he was gentle it could work between them, so they both wasted time following the wrong path.
The only thing that spoiled it was the crazy face he made almost at the end, I hate it when the author does this kind of thing to make the story more twisted than it is.
Katamuku Karada