After a much publicized split in July, Diddy's ex, Kim Porter is finally spilling the beans in a tell-all interview with OK! Magazine, where she speaks on everything from cheating, J-Lo and more.

Porter -- who has three children with the music mogul -- tells the mag, that after more than 10 years, they were still not on the same page, so it was time to "end it."

"I'd been in an on-again, off-again relationship with Mr. Combs for about 10 years, and it came to a point where it was time for me to move on with my life," Porter told the magazine. "I had invested a lot of time in that relationship, and it wasn't going where it should have been going. So it was time to [end it]. In a relationship, it's important that the people are on the same page at the same time. And we weren't on the same page."

As far as rumors of Diddy's philandering, she does admit that it happened, but doesn't specifically name anyone. "I will never sit here and say that Puffy -- or any man -- is 100 percent faithful," she explained. "I just don't believe it. Some of you are, but I'm not going to sit here and say that I didn't believe that he cheated on me. I would never say that. I'm aware that he's cheated."

She does go on record as saying that the reported love affair between Diddy and Sienna Miller did not cause their recent break-up because "they're just friends."

And she also calls Diddy's relationship with Jennifer Lopez "an embarrassment," adding that he was "still in love" with her during that whole period and never looked at it as "serious."

The entire interview will be in the next issue of OK! Magazine, which will hit newsstands on Wednesday (August 8).