Lopez recently reflected on the two-year relationship, which ended in 2004 when the actress called off their forthcoming wedding.
"I think different time, different thing. Who knows what could've happened? But there was a genuine love there," she told People magazine.
Lopez, 46, recalled that when she initially met Affleck, 43, "I felt like...'Okay, this is it.' [But] sometimes I feel like what you think people are and how you see them when you love them is different than when they reveal later."
It didn't help that the public and media constantly scrutinized their relationship as well, Lopez added.
"We didn't try to have a public relationship. We just happened to be together at the birth of the tabloids, and it was like 'Oh my God.' It was just a lot of pressure," she explained.
Lopez also reflected on her third marriage, to singer Marc Anthony. The two split in 2012 after nearly eight years of marriage and two children, 8-year-old twins Max and Emme.
The actress told People magazine the divorce "was devastating and awful," calling it "the biggest disappointment of my life so far."
"I think both Marc and I thought at the time we would be together for the next 40 years until we die," she said.
"I had been married twice before and I didn't want this to be a failure," Lopez continued. "I just put all my heart and soul into that and forgot who I was as an individual a little bit."
But after the marriage dissolved and she filed for divorce, Lopez said she felt a sense of "empowerment."
"It was the right thing," she added.
A rep for Lopez confirmed to ABC News that the actress indeed shared "her truth" in the revealing interviews.
Lopez is currently dating dancer Casper Smart.