Yeah it's silly, but I feel like people in comments go all of their way to ignore that Nishikata is embarassed to kiss Takagi in front of Chi. You all just go "He's embarassed to kiss her in their own house !"
Yeah it's silly but I kinda get it. Personally I don't have a kid, and I don't think I would be as embarassed as him in front of them, but I'm hella embarassed in front of my parents or in front of my partner's parents, I avoid to kiss my partner in front of them, and we have been living together for years now. This manga takes this kind of embarassment to level 5000 but that's a manga after all.