Ben Affleck and Jennifer Garner are debating having a fourth child.

The couple already have daughters Violet, six, Seraphina, three, and son Samuel who is five months old. While Jennifer is content with the size of their family, Ben is reportedly keen to add another baby to their brood.

"Jen is happy with three now that she has a boy," a source close to the family revealed. "Ben wants four."

Heartthrob Ben and actress Jennifer wed in 2005, but the loved-up couple show no signs of suffering from the seven-year itch and have one of the longest lasting relationships in Hollywood. The duo toasted their wedding anniversary at the end of June.

"The marriage is rock solid," confirmed the source.

The family will soon be heading to Puerto Rico where Ben, 39, is due to begin shooting his next film Runner, Runner.

Supportive wife Jennifer, 40, is never far from his side and has spoken out about how they make their partnership work so well. Sharing the responsibilities when it comes to their growing family and appreciating each other are often mentioned when she talks about their home life.