The 46-year-old "Feel The Light" hitmaker and the "Batman v Superman" actor began dating in 2002, when they filmed "Gigli," reported People magazine.
"I think different time different thing, who knows what could've happened, but there was a genuine love there," Lopez said.
The duo later starred in the movie "Jersey Girl" and the singer's "Jenny From the Block" music video.
Affleck, 43, proposed with a 6.1-carat pink diamond ring and they and got engaged. However, they called off their engagement in early 2004, just before their wedding.