"It ran its course. This industry is very tough on relationships," a source told People magazine on Tuesday. "Jamie thinks Katie is an incredible human being. They had a very, very deep connection. They brought each other a lot of joy and laughter."
The A-list duo was first linked in 2013, a year after the actress divorced Tom Cruise. For years, though, Katie and Jamie fought off speculation that they were an item, even after reported secret trysts and after photos of them kissing were published. Finally, Katie and Jamie debuted as a couple at the Met Gala in May.
People said the duo stopped seeing each other shortly after they made their official debut at the Met.
Us Weekly reported on Tuesday that the split simply came down to different lives… in a fairly extreme way.
"It has been many years of him stepping out with other women," Us' source said. "He's disrespectful and their lives were different. His partying ways don't fit with hers as she's focused on raising her daughter and working."
Katie was the one who ultimately pulled the plug on the relationship, Us reported.
Speculation that Katie and Jamie's romance was on the rocks caught fire last week when he was seen with a blonde woman at two Los Angeles nightclubs. A few days later he was spotted holding hands with singer Sela Vave.
Katie seemed to confirm the split news over a recent dinner, Page Six said, quoting a source who overheard her saying, "What Jamie does is his business — we haven't been together for months."