Kanye West is back on tour and is a single man. His engagement is now off with Alexis Phifer.

Says a source that knows the couple: “He broke up with her. Alexis still doesn’t really know what happened. It’s like she lost her best friend too. Things may change one day. He embraced her son and supported her business and her with all his heart. It’s just a rough time right now.”

Murmurs of a split began late last week with rumors erupting Monday morning over airwaves and blogs. A source close to the couple says that “Kanye is possessed by the tour and everything going on and just couldn’t keep it going. They are still friends and have broken up and gotten back together before, so it could work out.”

Says his former fiancee, Alexis Phifer: “It’s been hard and not been an easy time. I tried to keep things private but yes, it’s sad when things end like this and we truly do remain friends. I wish him the best in his future and all of his endeavors. He’s one of the most talented people I’ve ever met, that’s for sure.”

West, 30, proposed to Phifer in 2006 while vacationing in Italy.