
We only have access to the english translation in woopread and that is currently ongoing, so I can't tell you who it really is. The romance in the story is only currently 10-15% because the focus is Ashley's death & resurrection.
The spoiler about Amor (4th prince, the sick one) being the ML is from a commenter in the novel updates spoiler forum. They said they MTLed (machine translated) a blog in Naver. The commenter themselves is not sure, so we really can't tell. Another commenter has said that there is a mystery regarding Amor & Ashley's bloodline, so we really can't tell yet if this is incest. I'm sorry you're reading this long ass comment & not getting any concrete answer anyway, but it is better to clarify it than to jump in conclusions.
Don't give spoilers if:
* you're not reading the novel
* you copy pasted the spoilers but the source is not sure either about them or not credible
If you know the spoiler isn't 100% fact but you wanna share them anyway, put a disclaimer so other readers won't mistakingly drop the story because of your false spoilers.
And same goes for the readers, don't take all spoilers as the truth. I mean, sometimes it's obvious when the one spoiling isn't sure either