The singer filed papers yesterday which cited the "unreasonable behaviour" of estranged husband Ashley as the reason for their break-up, The Sun claims.
It is understood that the pair are likely to be granted a "quickie" divorce which will be finalised before footballer Ashley plays at the World Cup next month. Cheryl is not thought to be asking for a financial settlement and is expected to let Ashley keep their £6 million Surrey home.
A source said: "Cheryl made a swift decision to put England's World Cup dreams ahead of herself. The divorce should be finalised before England's first touch of the ball in South Africa on June 12. She knows how vital it is for Ashley to have a completely clear head and concentrate entirely on his football and performance, with no distractions or emotional pulls.
"She wants a completely clean break with no malice or wrangling over property or money. Cheryl will not take one penny of Ashley's money."
The papers filed yesterday reportedly state that Ashley "admitted" being unfaithful to Cheryl after his alleged sex texting was exposed in the press on February 15. Subsequent reports linked the Chelsea star to a number of other women.