The couple split just over a year after welcoming its two-year-old son, Bear, and the former One Direction singer thinks his track "For You", a collaboration with the "Hot Right Now" singer for the soundtrack to 2018's "Fifty Shades Freed", was the tipping point in their separation.
"(My duet with Rita) didn't do very much for my personal life," he told Closer magazine, but insisted he doesn't regret recording the song, adding, "Yeah, no, it was good."
The "Stack It Up" hitmaker went on to gush over Rita, adding: "I love her, she's really great and super, super fun to work with. Out of all my collaborations, I'd say she's one of my favourites."
While Liam and Cheryl remain on good terms as they co-parent their son, the former "The X Factor" contestant has moved on with new girlfriend Maya Henry, and insists the pair have "nothing to hide."
"I'm just past the point where I'm bothered about whether or not... it's not worth my happiness," he said in an interview on Britain's Capital FM breakfast show.