he isn't crying about his ex, to him, those five years didn't really happen so he was forced to let go and move on pretty quickly eventhough Taejoo was his rock since they were in cribs. It doesn't mean he still has feelings for him romantically. And he called his new man "his knight in shining armor who fights all his doubts" so he loves the male lead. Furthermore, i think it's unfair of you to just say that about the mc when Taejoo also thinks of the mc years later. AND even the ml thinks of his best friend years later and holds on to the picture. They all have their demons and they will help each other heal, that's how mature and comlex emotions work
idk the mc should stop bitchin and man up