There’s trouble in paradise for Justin Timberlake and Jessica Biel.

Pals say the two were having problems long before rumors circulated that the singer cheated at NYC nightclub Avenue late last month. Timberlake and Biel, a couple for two years, haven’t been spotted together since late May, and friends say their relationship is quickly going south.

“Things don’t look good for them right now — they’ve hit a really rocky spot,” confides a source close to Timberlake, who adds that serious problems began back in February during a boys’ trip to Las Vegas.

“Justin had to leave dinner once because Jessica was calling him incessantly. They got into a huge screaming match over the phone about how she’s always ‘checking up’ on him. She’s extremely needy and is always keeping tabs on him.”

The insider isn’t the only one who thinks Biel is a bother. “All his friends think she’s really annoying,” added the source. “She’s always trying to be one of the guys. She and Justin have no chemistry.”