Before Melanie McGuire — who’s infamously known as the “Suitcase Killer” — was convicted of murdering her late husband, Bill McGuire, and stuffing his remains in suitcases in April 2004, she was having an affair with her co-worker, Dr. Bradley Miller. More than two decades after the shocking crime took place, people are still fascinated with the murder and everything that went down in Melanie’s life before she was ultimately found guilty in her husband’s…