I think it Yunge wanted an opportunity to forget his difficult love, and Kensuke seemed like a safe choice since Yunge knows that Kensuke would probably go back to Hasekura / loves Hasekura. It was also an opportunity for Yunge to teach Kensuke what love actually is about (in general) and maybe shed light on the how is relationship with Hasekura was lacking.
I humbly agree, but the fact that Kensuke is in a relationship with Hasekura, and the fact that Yunge knows it, they shouldn’t have made such decision, and in front of Hasekura, too. Well, let’s say that at some point, Hasekura is at fault, and that both Kensuke and Hasekura are both still immatured considering that they are still young, however they should have known better than to make each other jealous or for whatever reason they did that (Hasekura sending Kensuke a picture of him and Masahiro, and Kensuke trying to learn about love with Yunge). No matter how you look at it, Kensuke trying to go out with Yunge even if it was just as a friend and for the sake of learning whatsoever, the fact that Kensuke is in a relationship should not be forgotten, Let’s not romaticize such things, in reality, that is considered toxic relationship.
i actually totally agree lol, i didnt like that yunge said that (what if kensuke took him seriously when yunge already has someone hes interested in). Maybe Kensuke didnt say no or clear up the misundersnating because he was getting payback for the picture (kensuke did says he did something bad to hasekura) I also though the break up was a but much, but i guess it did give kensuke time to process and move forward with their relationship. Haha i want to see kousukes reaction to the picture xD
As for Hasekura and Kensuke, I think they just lack communication, making Hasekura feel insecure in the process. Although I really don’t like how Kensuke easily went out with Yunge even just for a while, I still salute him for thinkjng things through and immediate settled his thoughts and feelings. But still, let’s not normalize going to another guy just because you got your heart broken or whatnot.