You’re wrong. She bedded Onassis and a host of others proving she was guilty of, at the very least, poor judgment.
That much is known. The rest of this are allegations made in the article. Jackie did not get along with the rest of the Kennedys, as they were only one generation away from bootlegging, had mob connections, and we know about the various scandals, rapes, drugs, etc., that went on with the family. She had a choice. Go into the Kennedy family, or find another rich guy.
She married Onassis shortly after Bobby was assassinated, and she desperately feared for the life of her children. She was close to Bobby (there are rumors he banged her a few times.)
Onassis was rich, but needed a trophy wife, Jackie needed someplace to get her kids where they wouldn't be the target of assassination attempts. A rich guy that owned islands was a perfect choice.