The couple have had a tumultuous relationship for sometime and now Hamilton, 27, had flown to Los Angeles to hear Scherzinger's explanation and try to save their romance, reported Femalefirst.
"Splitting was his decision. He's got a lot on his plate at the moment. And her commitments on X Factor and his career were clashing over the last few months.
"When he saw the pictures of her with Chris, he flew off the handle. He wasn't happy at all - even though they were not together any more. Lewis wanted to hear (Nicole's explanation) for himself," a source said.
Brown and the 34-year-old 'X Factor' judge were spotted looking intimate at an exclusive night spot last month, but the pair had insisted that they were simply talking to each other.