Infidelity part B. The 2nd is someone who no longer gets their human needs met, this is not always sexual needs. A person in a long-term relationship doesn’t one day just get up deciding to cheat on their partner. This happens through a long period of neglect, miscommunication and heedlessness of the other partner. We all naturally want to be loved, needed, valued and respected. When that diminishes at home and you get it from a colleague, a friend or someone you meet new, that craving of needs attracts you to that person, over time you fall for them and then the final act of expressing that attraction is being intimate. It is the exact way they fell in love with you.