Jen Garner and Ben Affleck’s divorce is getting uglier! As the two gear up for a custody battle over their three children, sources exclusively reveal to In Touch more and more incriminating evidence that could mean sole physical custody for Jen.

jen garner

Jen’s ammo? Ben’s issues with gambling and drinking and her belief that he may have cheated. “They’re gearing up for a pretty nasty custody battle,” an insider tells In Touch, adding that Ben’s reported links to other women could be “Jen’s trump card.”

Now, a source tells In Touch Ben is notorious for being a flirt — especially on-set.

RELATED: Were Ben and Jen Living Apart Pre-Divorce Filing?

While starring in and directing The Town in 2009, “He hit on [co-star] Blake Lively,” a source on the production exclusively tells In Touch.

blake lively ben affleck

Blake and Ben on the set of The Town.

blake lively ben affleck

Blake and Ben on the set of The Town.

“But she wasn’t interested at all,” the source continues.

For more details on Jen and Ben’s divorce, pick up the latest issue of In Touch Weekly, on newsstands now!

For access to all our exclusive celebrity videos and interviews – Subscribe on YouTube!