Here we introduce the case of the future President Kennedy:
There are some clear differences. We don’t have full length research by a doctor of history, as we do for Edward IV. American law doesn’t allow for the “per verba de praesenti/ de futura” secret marriage and there would have been official records and witnesses. The 1545-63 Council of Trent also banned the concept of secret marriage throughout the Catholic world, to which the Kennedy family belonged. There are American states in which divorce and annulment are exceptionally easy.
There are similarities as well. Both men were members of very powerful families, with the opportunity to intimidate or persuade inconvenient witnesses, but Kennedy’s father was still alive.