Jack & Jen
Jennifer Horton and Jack Deveraux first got together during the Cruise of Deception.  When their boat was shipwrecked, Jack, who had been trying to deny his attraction to Jenn, finally professed his love for her, and they slept together(in a cave).  They both worked for the Spectator, a Salem newspaper.  Jack covered the police beat for the paper, and Jenn later left the paper and became an on-air television reporter.  They were married in 1991 at a Wild West show in Hollywood, where they stayed for their honeymoon.
In 1993, their young daughter, Abigail, was diagnosed with aplasmic anemia.  Austin provided a bone marrow transplant.  Jack discovered that while he worked for his father, he had signed some papers that allowed toxic waste dumoing, which had caused Abby's sickness.  Jack was overcome with guilt and left town. 
Jack returned to Salem in '95 to fing Jenn in love with Peter.  Jenn did not want to renew her relattionship with Jack; she insisted that she had moved on.  Jack set out to prove that Peter was no good.  In the next few years, after Jenn married Peter, he did prove that Peter was a true DiMera, if not by birth.  Jenn filed for divorce.  Peter tried to kidnap Jennifer , and Jack tried to stop him and their was a struggle for the gun and Peter was shot, but Jack ended up being blamed for Peter's murder(he later turned out not to be dead after all).  A man named Travis kidnapped Jenn, and jack broke out of jail to find her.  Jack and Jenn(and Abby) went undercover in a circus to hide.  Jenn faked her own death and appeared at her funeral as a ghost to get Peter to confess.  He did, and Jack was freed.  Jack, Jenn, and Abby then left for an Afican saffari.  But something changed in Africa; Jack wasn't around much, and Jenn turned to a handsome Irish doctor for comfort.  She followed him all the way to Ireland.  They all came back in Salem again, Jack, Jenn, Abby and the doctor.  Jack and Jenn were separated, but they worked together to uncover the mystery of this Irish doctor, Colin Murphy, a cousin of the Bradys.  Colin was killed, and Jack and Jen got back together, remarrying in 2003.  Unfortunately, Jack became a victim of the Salem Stalker, and was once again separated from his family.  Jennifer was now pregnant, and she went to the island looking for Jack, who is still alive.  Jennifer now fights to save Jack and her soon-to-be born child.