When: 1941-1967

This one is truly a love triangle for the ages. Legendary actor Spencer Tracy was married to Louise Treadwell, who also went by Louise Tracy, for 40 years. The two remained wed until Tracy passed away in June of 1967. However, for more than 26 of those years, Tracy carried on a secret love affair with Katharine Hepburn, the iconic actress whom he co-starred in nine movies with. As legend has it, Spencer remained with Louise all those years for fear of causing the couple's two children, John and Susie, humiliation and heartache. 

Both Hepburn and Treadwell were present at the cemetery when Tracy's body was laid to rest.

Only in Hollywood.