
Min is not abusive.
Emotional abuse is a PATTERN of behaviors. If you say something mean to your partner, it's just mean. If you're constantly putting your partner down, it's verbal abuse. Shin was emotionally abusive because he was in a position of power over Min and had a pattern of manipulating, controlling and shaming him. And that kind of relationship is incredibly hard to talk about, not just because it reopens old wounds, but because of the misplaced shame and self-blame, and the (not irrational) fear of being judged.
In keeping his secret, Min made some bad decisions that hurt Sijun, but they were just mistakes. Sijun didn't forgive him because he's brainwashed, he just loves him. He still needs to process some emotions, and he still can. They still have things to talk about, and they still can. But they just went through a major hardship in their relationship and they deserve to relax and be happy for a while. Every relationship has problems, they just need to learn how to work through them together maturely, because they're both new to this.
I feel bad for red head but I don't blame the other guy at all. If someone almost killed my best friend and then said it was a mistake because they actually meant to almost kill me, I don't think I'd be mean to them too.