The 41-year-old 'Dallas Buyers Club' star, who raises daughters Violet, 8, Seraphina, 5, and son Samuel 2, with Affleck, 41, will not be having anymore children, she has told a friend, reported Radar online.
"Jennifer told her pal that the difference between having two kids and three is massive and Sam would complete their family," a source said.
"In fact, Jen admits she and Ben had only planned on having two children, and Sam was a wonderful but genuinely true accident.
"They love their kids, but she is really had her hands full with three since Sam was born in 2012 and while things are starting to settle down, it has been pretty exhausting, especially with Ben being so busy," the source added.