The 'Under The Sun' singer was devastated when Ashley's infidelities were revealed and went for tests to make sure she wasn't at risk, reported Contactmusic.
Writing in her new book, 'Cheryl: My Story', she says, "His infidelity had been putting me at risk for a long time. I had to put my mind at rest. I was sad, sick and felt fury like I'd never experienced," she added.
Cole divorced the England soccer player in 2010 following revelations he had cheated on her with a string of women.