All is not well for Ciara …

Just three months after giving birth to their son Future Zahir Wilburn, the singer has called off her engagement to rapper Future after discovering that he cheated, reports Us Weekly.

"He cheated on her. Game over," an insider tells the mag.

Another source commented,"She's devastated. Ciara's focus now is the baby."

The "Turn On the Lights" rapper proposed with a 15-carat diamond ring on Ciara's birthday, October 2013, in New York City. Seven months later, the 28-year-old gave birth to their son on May 19.

TMZ is also reporting that Ciara has their son and and plans on getting custody.

Unfortunately this love story doesn't have a happy ending …