The 29-year-old actress, who married the Tennis player on December 31, 2013, is "secretly worried" about her relationship, reported OK! Magazine.
"Kaley is really paranoid... She doesn't let him out of her sight. She always asks Ryan who he's with and never knows what he's doing. She'd flip if he didn't answer his phone. And it drives him crazy," said a source.
"She is secretly worried she doesn't know him that well."
The "Wedding Ringer" star had previously denied rumours of her relationship with Sweeting was on the rocks.