Untold Stories of Carolyn Bessette-Kennedy, 18 Years After She and JFK Jr. Were Killed in Plane Crash

John F. Kennedy Jr. was at the controls when the plane carrying his wife and her older sister went down off Martha's Vineyard.

Carolyn Bessette-Kennedy kept John F. Kennedy Jr. waiting for nearly three weeks before finally saying yes to his proposal.

Read: Did Robert F. Kennedy Stray in His Marriage? New Book Reveals Shocking Rumors of Infidelity

It's just one of the stories in the latest issue of People magazine out Friday, commemorating the 18th anniversary of their tragic deaths.

The magazine features rarely seen images of a young Carolyn. Both she and John were thrilled when they pulled off their surprise wedding on Cumberland Island off Georgia in 1996.

The couple's passion also lead to arguments — including an infamous confrontation in New York's Central Park that was caught on video. 

The strain of life in the spotlight was something she never got used to.

She was rattled by the death of Princess Diana in 1997 after a paparazzi car chase in Paris, France.

The couple often fought in the weeks leading up to that fateful day when Kennedy piloted a plane with his wife and her sister, Lauren, to Martha’s Vineyard.

Rosemarie Terenzio was his assistant for the final five years of his life.

She says she often refereed their fights, but the couple always patched things up.

Read: Rosemary Kennedy's Dad Ordered Her Lobotomy to Prevent Pregnancy, New Books Claim

"They had fun together," she told Inside Edition. They laughed a lot. they were buddies."

Their close friend Carole Radziwell, who now appears on The Real Housewives of New York City, told People, "To say their marriage was on the rocks is just inaccurate."

Watch: JFK's Grandson Remains Coy About His Political Future