Humphrey Bogart
Humphrey Boggart, then 46, left his wife Mayo Methot after having an affair with his 19-year-old costar Lauren Bacall on the set of To Have and Have Not, possibly the most famous case of a celebrity leaving their spouse for a mistress in Hollywood history. Boggart was clearly infatuated, as he married Bacall six months after their divorce and stayed together for the next 12 years until his death.
Jennifer Aniston
Jennifer Aniston and Justin Theroux co-starred in the film Wanderlust in 2012, and the two supposedly started dating on production. Theroux left his 14-year girlfriend to publicly initiate a relationship with Aniston less than two years later. In 2015, the couple married, and in 2018, they filed for divorce.