Sean 'Diddy' Combs Reportedly Suspects Ex Cassie of Cheating on Him With Someone He Introduced Her To

Sean "Diddy" Combs suspects his ex-girlfriend, singer Cassie Ventura, of cheating on him with her personal trainer, who he hired for her while they were dating.

According to PEOPLE magazine, a source claims that Diddy believes Ventura started her relationship with Alex Fine, a professional bull rider, before her relationship with Diddy ended.

Ventura introduced Fine to her Instagram followers on Saturday, posting a photo of the two of them sharing a kiss on the lips.

The two reportedly met when Diddy hired Fine to be her personal trainer before their breakup in October, and Diddy reportedly believes that "there was absolutely overlap."

"Cassie wanted a personal trainer, so Diddy hired Alex for her. Then Cassie and Alex started hooking up before her relationship with Diddy was over," the source said.

Ventura's PDA-packed post with Fine, which also included a shot of the two of them with her mother at a holiday party, came one day after Diddy shared a sensual photo of Ventura. In the photo, she appeared to be taking a bubble bath; Diddy added a heart emoji over the top of the image and tagged her, although she no longer follows him on Instagram.

The two dated for 11 years before splitting up in 2017, with a source telling PEOPLE they broke up months before it was announced in October. A source told the magazine that "the decision as amicable and they remain friends."

"Cassie is going to focus on her music and acting career," the source continued. In the wake of the breakup, Diddy was linked to model Jocelyn Chew; the two were spotted together in Miami as well as a Drake concert in Los Angeles.

Combs and Ventura met in the early 2000s when she signed onto his Bad Boy Records label. Dating speculation began in 2007 and continued through their working relationship, when they collaborated on his 2008 song "Swagga Like Puff" and her 2009 song "Must Be Love."

In 2013, Ventura told Madame Noir that "Just being around [Combs] is a completely inspiring experience. The key to maintaining any relationship, be it a romantic relationship or a friendship, is honesty and communication."

In June, Combs told Wendy Williams on her eponymous talk show that she was "in love now." But by October, Ventura had not posted about Combs in several months and was not following him at the time. In fact, she was only following one account.

Combs is a father to six children — sons Quincy Brown, 27, Justin, 24, Christian, 20, twin girls D'Lila Star and Jessie James, and daughter Chance, all 11, through previous relationships with exes Misa Hylton-Brim, Kim Porter and Sarah Chapman.

Porter, 47, died unexpectedly a month after Diddy's breakup with Ventura was reported. While giving her eulogy, Diddy revealed his struggles with depression, sharing that that Porter helped him through the difficult times.

"I was getting older, and I just went through a dark, dark time," Combs said, according to a video from the service obtained by TMZ. "And even though we wasn't together, she was that type of person. She would come over and...she was just like, 'Come on, Puff. You gotta get up. You gotta get up out the bed. You gotta get moving. You gotta get up.'"

The two dated off and on from the '90s through 2007 and shared children Christian, D'Lila Star and Jessie James.