Origin: Cindy and Libby were stranded together for 48 days after the crash of Oceanic Flight 815.
Since Then: They spent over forty days together, in which they did many things. They fished together, made decisions together, moved constantly around the island together. They were together when they found the Arrow Station and when Jin washed ashore. They're both kind and sweet and didn't agree to what Ana Lucia was doing to Nathan.
Since Then: David never appeared on Lost, but he affected Libby greatly. The two were husband and wife, and when David died, Libby suffered a mental breakdown and had to check herself into Santa Rosa. Despite this, Libby did not appear to think of him after death, and the two did not move on together. She instead awoke with Hurley, a man she knew for less than two weeks.
Origin: The two shared a line for coffee. Desmond lacked American currency to pay the bill, and Libby offered to cover it.
Since Then: Desmond jokingly asked for a further $42,000, and when Libby pressed him for details, he explained he needed a boat for Widmore's race. Libby lent him one her late husband gave her. Desmond set sail, and the two never met again while alive, though both coincidentally ended up on the Island for a period years later. Desmond tried to escape it in Libby's boat, and he returned just as the survivors were holding her funeral. After death, Desmond helped connect Libby with Hurley, and he watched from afar as they kissed.
Origin: Hurley became interested in Libby when she joined the castaways.
Since Then: The two slowly formed a relationship that culminated with a kiss. Libby was a positive influence on Hurley as she tried to get him to stay healthy on the island. Following a suggestion from Sayid,, Hurley decided to take Libby to a secluded area on the beach for their first date. When Hurley forgot to bring blankets, Libby offered to retrieve them from the hatch. Michael, startled by her appearance after having just shot Ana Lucia, shot Libby in the stomach. Hurley watched her die, dug her grave and spoke at her funeral. Hurley visited her grave regularly for the rest of his time on the Island, but though ghosts began visiting him afterward, Libby's never did. After death, he ran into Libby when a blind date stood him up. He learned she was a Santa Rosa inmate, but her pursued her regardless and eventually took her on a beach picnic that replaced the date they'd missed. They kissed, waking him up.
Origin: Libby discovered Jin's body washed up on the beach after the raft explosion.
Since Then: Libby couldn't understand Jin's Korean, and each suspected the other as an island native. Once they realized they were survivors from the same crash, they traveled together across the Island. Libby followed Jin's instructions for caring for Sawyer. She encouraged Michael to leave Jin and obey Ana's demands for supplies, and later convinced Ana to let Jin return to his camp. Once the two camps had merged, Hurley and Libby tried to go on a picnic. Libby pointed out Jin to prove that they had arrived at their own beach rather than another.
After death, Jin and Libby greeted each other in the church before moving on.