Ben Affleck has moved on! He's the happy dad, taking care of his kids every day -- school drop-off and pick-up and froyo runs and everything -- and it seems he's let his relationship with Lindsay Shookus go ... 'cause she's moved on, too!

Shookus shook us with the news she is hanging with hottie Mad Men actor Jon Hamm in New York. The two were spotted Broadway show Derren Brown: Secret on Sunday on a date! According to an Us Weekly source: "The two sat next to each other and Jon was right next to the aisle. They weren’t hiding anything! Lindsay and Jon didn’t show much PDA, but there was definitely some flirtatious banter. Lindsay turned her head to talk to Jon before the show, during intermission and after the show. She was always smiling and looked like she was enjoying her conversations with Jon."

The two left separately and another source tells the mag the two have been friends for decades and have a platonic relationship. But hmmm ... what do YOU think?