For sure, jinwoo knows that his own cold behavior is the one who caused the breakup. He realized that he's the one who changed and dropped out of love hence using tiredness as an excuse. That is why he was shocked when he realized the truth and regretted his actions. I think that there's a part of him that still love Candy. He was regretful about hurting Candy all along and thought about asking the past him to break up with past himself so that he could find someone better. But when it really comes to the ending when present Candy is back, he still want him to stay although it maybe selfish of him. And I think him sleeping facing Candy again shows that he still love Candy.
But anyway I hope his love for Candy is still sincere.
I hope too.
The realness of the situation hit too hard
The ending is not clear.
I mean I don't know if jiwoo still love him.
He wasn't even aware that he was being cold and distant.
He just started feeling guilty after reading the diary.
I think that he was feeling sad about the break up because after 10 years of being with someone leaving them is hard.
Anyway I think he doesn't love him anymore but is just feeling guilty.
Sorry I just don't feel the happy ending.
I mean they didn't see each others for days and when they didn't the was no communication and the guy was fine with it.