The two dated after her divorce from Arthur Miller sometime in the 1950's. Marilyn stayed with Frank when she moved back to Los Angeles and the relationship ended in 1961 when he proposed to Juliet Prowse.
It was widely known that Marilyn was a good friend to both Dean and his wife Jeanne but rumors were spread that Ms. Monroe was taken with star-studded singer which led to an affair. Unfortunately it was only a rumor.
Jose was a screenwriter and director an a bit of a playboy. He escorted Ms. Monroe to the Golden Globe Awards in 1962 and claimed that they were going to get married which many people believe to be false.