When Roland and his Ka-tet arrived in a town called Hambry, he slowly fell in love with Susan Delgado, a young girl whose father had passed away. She had been selected, against her will, to become the second wife of the mayor of the town, a man roughly 30 years older then her. This was because the mayor's current wife was unable to bear him a child. While Cuthbert and Alain tried to find out more about a possible uprising against GIlead, Roland, in the heat of the moment, slept with Susan and impregnated her.
Large numbers of people were angry and resentful towards Gilead and their king, Steven Deschain. They soon came into contact with a group known as the Big Coffin Hunters, led by Eldred Jonas, an exiled Gunslinger. The situation soon took a turn for the worse, as the town found out about Roland's affair with Susan Delgado and the mission of the Ka-tet.
A fight erupted. Roland had to leave Susan behind, safe in her home. However, during the fight Roland and his Ka-tet were in, Susan was killed by the townspeople for breaking the oath to the Mayor and therefore branded a witch. She was sentenced to die by fire. After the fight, Roland witnessed her death at the hands of the townspeople through one of "Maerlyn's Grapefruits".
Susan's death haunts Roland to this very day.
The Journey Begins
Years later, after the battle of Jericho in which Roland lost all of his loved ones, Roland traveled to a town and visited a bar. The maiden at the bar bore a striking resemblance to Susan Delgado, even bearing the same name. It however turned out that it was not a re-incarnation of Susan Delgado. This did not stop Roland from saving this Susan when she was taken by the 'invisible man'. After their shared adventure, the two parted ways.
The Dark Tower IV: Wizard and Glass
Roland, Eddie, Susannah, Jake, and Jake’s pet bumbler survive Blaine the Mono’s final crash, only to find themselves stranded in an alternate version of Topeka, Kansas, one that has been ravaged by the superflu virus. While following the deserted I-70 toward a distant glass palace, they hear the atonal squalling of a thinny, a place where the fabric of existence has almost entirely worn away. While camping near the edge of the thinny, Roland tells his ka-tet a story about another thinny, one that he encountered when he was little more than a boy. Over the course of one long magical night, Roland transports us to the Mid-World of long-ago and a seaside town called Hambry, where Roland fell in love with a girl named Susan Delgado, and where he and his old tet-mates Alain and Cuthbert battled the forces of John Farson, the harrier who—with a little help from a seeing sphere called Maerlyn’s Grapefruit—ignited Mid-World’s final war.