Honestly, Taeyoo is so patient. I could not be in a relationship with someone like Jae-in. Imagine having a kid with someone and being in a committed relationship and they continually hide things from you but are fine telling others. That would be a huge dealbreaker for me. Obviously, Jae-in doesn’t trust Taeyoon’s feelings for him but aside from this, keeping the truth about his own father from him is cruel. Like this is his life and he’s entitled to know. The fact that Jae-in is keeping this from Taeyoom when Taeyoon has already communicated that he’s bothered by him hiding things shows that Jae-in thinks that he knows best and is okay to disregard his partner’s feelings. Having insecurities could be his excuse but it’s not a good enough one. A refusal to communicate problems to your partner screams of a shaky foundation to a relationship. I would hate coming home knowing there’s a huge problem that everyone but me knows about and then being forced to pretend things are okay. I also couldn’t raise kids with someone who doesn’t trust me.