I can understand empathizing with the ex, i DO agree that it must've been shitty being the only one open about their relationship, but he definitely handled things wrong. He outed him to his parent... Idk if you're gay or not, but i can't stress that enough to make you understand the significance in that. I'm a gay man, i'm one of the lucky ones that didn't have it particularly hard, but even I had insecurities with telling my mom i'm gay. I didn't tell her till junior year of high school, i knew i was since middle school... There is something terrifying about telling your parents specifically, idk what it is, maybe an irrational fear in cases like mine? It's a lot of mental anguish. It sucks, but you can't FORCE people to be "out", you have to support them till they can be on their own. The uke was lucky, his dad was okay with it, but the ex's actions could've literally destroyed a family. He could've been disowned, things are pretty strict over in Asia. It was just... Wrong. Reading that gave me this sense of nausea. If he couldn't handle his partner not wanting to be open at the time, he should've broken up with him, BECAUSE if you can't, it hurts. It takes a specific amount of patience and understanding to date someone who is in the closet.
Nobody is to blame the ex because what he says is true. The Uke had a guilty conscience. The poor ex had to shuffle in a one sided relationship. I hope the ex moves on and finds someone who'll face their relationship properly and heal the scar the Uke left on him. the ex doesn't like the Uke he's merely stating the truth of how the Uke is a coward. The Uke and seme's relationship was doomed to fail if the Uke couldn't break his fear so it's a good thing the ex is doing this. All the people hating the ex don't know how he felt and frankly don't understand how important he is to the character development of the Uke