Can you imagine the guilt this guy placed upon that girl? He practically hard labeled her "homwrecker" for the rest of her life. Then, adding on the paranoia of "once a cheat, always a cheat". I also noticed in the flashback that he never wore his wedding ring. She likely never knew he was currently married till shit hit the fan. So let's add worry over lying to that ever growing tally.
Hopefully this girl doesn't follow through marrying him after the divorce is finalized and let's this man wallow in loneliness till he dies.