While that was the excuse Yoshioka gave to the MC, tt was revelaed that Yoshioka had genuen feelings for the MC but didn't want to hurt Kaori by stealing him. It seems that after the MC was dumped, he and Yoshioka started a relationship. However, Yoshioka is a model and her being in a relationship might damage her career. I think her manager gave the MC money to pay him to break it off with Yoshioka.
He rejected the money, and the manager said: "So that is the difference between us, you have morals".
And for the most part it seems like such a weird love triangle, Yoshioka had legit loved him longer than Kaori has, Kaori knew Yoshioka liked Takeru and confessed to Takeru because she also fell in love with him.
Then Yoshioka made her moves on Takeru which led to their affair, the Kaori saw them do it but kept quiet because she knew she liked him before she did so she probably felt guilty that she got him before Yoshioka got to make her move.
Then Takeru confessed to the affair, broke it off with Yoshioka and then after that Kaori likely felt guilt again and decided to break up with Takeru so he could be with Yoshioka but when she broke up with him, Takeru chose Kaori instead but she stuck to her idea of breaking up.
Then Yoshioka got together with him for a short time, she saw that he rejected the money and decided to break up with him so he could be with Kaori.
And it feels like Kaori will be trying to get back with him soon.
I know he isn't faultless in this whole thing but I really feel bad for him with how he is being ping-ponged around by these two women.
He made a mistake by cheating but the relentless barrage of seduction would be difficult to resist for long by most people, it takes a lot to resist constant attempts at seduction, they just need you to give in the one time and that is all it takes.
In the words of the IRA, you have to succeed all the time, we only have to succeed once.
Poor dude lost his whole family, nearly commited suicide, feels like he suffers from depressive episodes, and is now being jerked around by these 2 girls who both love him