Ben Affleck's rep may have denied that the actor cheated on estranged wife Jennifer Garner with sexy Suicide Squad co-star Margot Robbie, but now Us Weekly is reporting that Ben definitely cheated with SOMEBODY, and he actually told Garner about it!

While a number of news outlets have stated that the reason for the split was primarily Ben's absence due to his busy work schedule, multiple sources tell the mag that Ben's "partying, gambling and, yes, inappropriate behavior with other women" was the real cause. Tell us more!

One insider says Garner told her friends that Affleck had “admitted to cheating with an attractive love interest," and this was around the time she kicked him out of their Pacific Palisades home, "but eventually decided to forgive him." Not for long!

Apparently this was a pattern with the couple, as another source tells the mag, "She tried to leave him a few times, but he would beg her to stay ... She always fought against the urge to throw her hands up in the air and walk away. They’ve been on the brink of splitting up many times before, but it’s Jennifer’s worst nightmare for their children. Her biggest desire has always been to keep the family together."