Not all loves last a lifetime.

Helen Hunt and Matthew Carnahan have broken up after 16 years of dating. "She has been split up with Matthew for several months. They had a

Not all loves last a lifetime.

Helen Hunt and Matthew Carnahan have broken up after 16 years of dating. "She has been split up with Matthew for several months. They had a rocky relationship and many offs and ons over the years. They stayed together as long as they did because of their daughter," a source close to the actress tells E! News. "They've split up before, but this time seems to be different."

Hunt, 54, and Carnahan, 56, had been together since 2001; they share a 13-year-old daughter.

Carnahan also has a 20-year-old son from a previous relationship.

(The actress, who won an Oscar in 1998 for As Good as It Gets and multiple Emmys for her leading role in NBC's Mad About You, was married to Hank Azaria for 17 months in the '90s.)

In Touch first reported news of Hunt and Carnahan's breakup Wednesday.