"Courteney had fertility treatment before she had Coco and doesn't want to endure it again, and she's dead-set against adoption. She's 44 now and they've essentially given up on their dream of a second baby," a source said. "They've had major ups and downs in the past, but this time they both seem at the end of their tether and just exhausted," the source added.
Courteney is reportedly worried the stressful situation might become too much for her 37-year-old husband, who has battled problems with drugs in the past. The source added: "Courteney's really hoping they can get through this. But David seems more interested in going out with his mates."