Agreed. He clearly suffers from depression. I saw hints of it in earlier flashbacks (both his mom's and his brother's). You can't judge someone with that level of depression, especially with the suicidal ideation, like someone without. Like you said, it messes with your mind and makes you firmly believe the people you love will be better off without you.
Also, the fact that he clearly regrets how much he's hurt Minho, and acknowledged that his choices traumatized his son are strong indicators that he does truly love Minho. He just thinks he's the problem, that Minho would be better off without him. When in reality Minho needs him, and him not being around, not being stable, etc is damaging to Minho.
I think that whole family needs therapy. ML, his brother (who probably needs antidepressants), his mom, and Minho (dad is no where near ready for therapy, he needs a strong dose of reality first). FL also could use some therapy but she's clearly done a lot of work on herself already.
Anyways, those are my thoughts. They seemed to align with yours so I shared them here.
Some of y’all don’t understand how severely blinding suicidal thoughts can be. They convince you that you’re unloved, a burden to everyone around you, and that it would genuinely be better for everyone if you were gone. I’ve been there myself. I obviously didn’t have a kid at 14, so I don’t know how knowing you’re responsible for another life would affect things, but suicidal thoughts can genuinely make a person believe that their child would be better off without them too. It was selfish of him, sure, but he clearly wasn’t in his right mind.
And I don’t know why some of you are saying “it’s just a divorce” and that he had no reason to be upset to the degree that he attempted to take his own life. That can push someone over the edge. You can be suicidal without having to experience something life-altering. Could he have done better for his son and himself since the divorce? Absolutely. But don’t put all the fucking blame on him when he was the one cheated on, and his own mother refused to even help him. I’m not saying he’s innocent, but he’s not a monster. He has his brother helping him now, and he’s clearly working on himself.