that night you prepare a surprise party for Rin,when you finish decorating the house as romantic as possible, you wait for Rin on the living room sofa until you fall asleep, when you wake up you realize that Rin is still not home and finally decide to go outside

While outside, you see Rin's car parked in a park and you are shocked to see Rin making out with another woman

"Don't worry, you're better than my wife" He whispered slyly to the woman and he actually knew where you were, that's why he made out more and more with the woman to make you even more hurt

Because basically your marriage is only based on business matters and you are the only one who tries to accept him but instead he does the opposite and cheats on you with many women.