From Brokeback Mountain to broken up. Sources close to Heath Ledger and Michelle Williams aren’t surprised the duo of three years — and parents of
Matilda, almost 23 months — have parted ways.

“They have been broken up, on and off, since Matilda was born, and tried in many ways to make it work for her sake,” a Ledger source tells Us. Now more than ever, “Matilda will remain their first priority.”

Indeed, the day news of the breakup surfaced, Ledger, 28, brought his mini-me to NYC’s Children’s Museum of Manhattan. On September 3, Williams, 27, and her daughter hit a cafe in their homey Brooklyn ’hood. So what went wrong? It may have been too much, too soon for the Oscar-nominated pair, who began a whirlwind romance on the set of Brokeback Mountain in summer 2004 and became parents in October 2005.

The past year or so has been filled with ups and downs, as the duo spent “a few months apart and barely spoke,” according to a source. Now the two are working to make the split easy on their girl. “You’ll see them together again,” a Ledger source tells Us. “It won’t mean they’re back on, but they’ll be spending time with Matilda.” (The couple’s rep had no comment.)