The OP on r/popculturechat did a nice slideshow including:
Ethan Slater left his wife for Ariana Grande after they starred in ‘Wicked’.
Ewan McGregor left his wife for Mary Elizabeth Winstead after they starred in ‘A Gentleman in Moscow’. Fargo
Stanley Tucci left his wife for Edie Falco after they starred in ‘Frankie and Johnny in the Clair de Lune’.
Thomas Kail left his wife for Michelle Williams after they met on the set of ‘Fosse/Verdon’.
Ted Danson left his wife for Whoopi Goldberg after they starred in ‘Made in America’.
and additional ones from the comments:
Stephen Moyer left his partner of 17 years for Anna Paquin, his true blood costar
Josh Dallas left his wife for Ginnifer Goodwin during Once Upon a Time
Hugh Jackman is a recent one
Eddie Cibrian and LeeAnn Rimes…how could we forget. That’s some good drama for the young ones to learn about
James Tupper left his wife for Anne Heche after they starred in Men In Trees together.
Ryan Reynolds was married to Scarlett Johansson when he filmed Green Lantern with Blake Lively.
