
we are still far from knowing about ML feeling, but if you are curious (I'm a curious cat, I've been binging on reading it untul the end), you can read the novel. It's really mind blowing, with the plot, and how the story end, the reason behind his regression. I really like it. we will knew about their back story.

Major Spoiler
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All of them actually regressed. So literaly the ML found a way to turn back the time but that ability made all of them lost their memory except the one he wants to rescue(MC). Thats why MC have all his previous memory intact.
And actually, the scene from first chapter are more complicated than what showed. So, when mc catch his last breath he guiding the ML, and all his feeling being transfered to ML (this can happen if they can't control their mind), in short, ML knew MC feeling for him, that MC apologized for all the bad thing he done to ML. And you know what by the time MC died ML realize that he also have feeling for MC. A late realization that he is infact love MC.
After so many years he finally found a way to turn back time.
I hope the manhwa will include all element from novel. Oh, and about ML fiance, even from previous life they aren't actually in real relationship, the girl guide looks like ML late mother, he only use her so that his parents (especialy step mother) think that ML still furnerable and can control.
After reading some spoiler here, now I'm wondering. If he's that obsessed with the mc why in the first chapter ml still hugging the woman even though mc is dying not far away from them.