Cassie dumped Diddy for her Caucasian personal trainer.

Diddy and Cassie are officially over, and she's left him for her personal trainer.

Cassie publicly announced thats he and Diddy are through, and that she's seeing celebrity personal trainer Alex Fine. Alex trains a ton of celebrities, including NY Giants star Odell Beckham Jr.

Here's the pic that Cassie posted, confirming their relationship:

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Cassie and Diddy have dated for more than a decade, during which Diddy continually cheated on her. Earlier this year, Cassie told him she had enough, and dumped the billionaire rap mogul.

But when Diddy's babys mother Kim died suddenly, Cassie and Diddy got close again - and many thought they'd reconcile.

Cassie was seen with Diddy shortly after Kim Porter died last month ... which sparked rumors they might be rekindling their 10-year relationship following their October split.

Looks like that reunion was just moral support though,Cassie hasn't been spotted with Diddy since. 

Here are pics of Cassie's new man: