Actors Heath Ledger and Michelle Williams have decided to call it quits after three years and one child (Matilda) together.

“It was rocky for awhile,” says a source close to the couple. “They did what they could to make it work.”

The pair, who welcomed daughter Matilda in October 2005, met while they were filming Brokeback Mountain in 2004.

Costars say the chemistry was obvious from the start. “I remember being in rehearsal, and the two of them had googly eyes with each other,” costar Jake Gyllenhaal said of the couple. “There were sparks immediately,” added costar Anne Hathaway. “It was adorable.”

Ledger has really fallen off of the map the past couple of years. Whereas Brokeback Mountain seemed to propel Jake Gyllenhaal’s career to new heights, it has had the opposite effect on Heath’s.

Heath does play the Joker in the upcoming Batman film.