Cry him a river!

After four years together, on-again/off-again couple Justin Timberlake, 30, and Jessica Biel, 29 are once again on the outs, a source close to the couple tells

"It was mutual," says the insider. "Jessica is doing well."

The pair began dating in January 2007 and were

often the subject of split rumors.

Last year, Biel told Vogue of her relationship, "It's the most precious thing that I have in my life, and I care so much about it that I don't care about what anyone else says or thinks."

More at