Kayo does have other reasons, but the root causes are those I gave above.
The biggest issue is Kayo took MC for granted. Think of the difference between a hot, crazy and your average, reliable partner. The hot, crazy one is exciting, but you would never want to spend the rest of your life with them. Kayo views MC as the one she wants to marry, start a family, and spend the rest of her life with. Kayo was surrounded by slutty bitches all her life. Her basketball members are slutty, cheating bitches that were the ones pushing for Kayo to cheat in the first place. Her mother also cheated on her partner. The difference with her mother is that the partner decided to accept another person's child (Kayo) and marry her mother.