I somewhat disagree. He was pretty repentant because he realized that he did abuse the fuck out of Dan for his intense desire to win at all costs and was the reason for Dan’s sleepwalking and trauma. That’s why we see him doing everything he can to make Dan’s life comfortable and trying to set Dan up to be able to provide for himself and his grandma after they part. Jaekyung realizes that he is in love with Dan and genuinely wants Dan to stay but believes he has no right to ask him.
Now he just realized that how bad things were for Dan that he agreed to a sex contract despite being a virgin and a victim of sexual assault from a scumbag doctor who wrecked all the hard work and sacrifices Dan made to finally get a career that could have provided for his grandma and pay off loan sharks. And despite the shit Jaekyung put him through, Dan was still able to fall for Jaekyung because Jaekyung made him feel that he accepted Dan and gave him a place that he belonged, something Dan had denied himself when he was locked in to become independent as quickly as possible for his grandma.
Jaekyung already feels unworthy of Dan but now he realizing that he wasn’t really that much different from that rapist doctor with him assuming that Dan was experienced due to how beautiful he was that Dan must’ve had guys lining up wanting to fuck him. It’s going to unlock a new level of emotional hell for Jaekyung and I do hope Mingwa actually show us.
I guess I understand now why Jaekyung doesn't seem as repentant as I thought? He's just now realizing the extent of his actions