Rihanna is ''forever thankful'' to Chris Brown.

The 'Diamonds' hitmaker is reportedly indebted to her 25-year-old ex-boyfriend for teaching her to be more ''humbled'' and was upset when he started dating model Karrueche Tran.

A source told HollywoodLife.com: ''Chris Brown broke her heart and stomped on it when he brought Karrueche into the picture.

''Rihanna didn't understand why Chris made her compete with another b***h. Like, she's Rihanna. She could have any dude.''

The source added: ''On the real, the one thing Chris did for Rihanna, which she will forever be thankful for, is that he humbled her. He was the first man to let her know it's not always about her.''

Meanwhile, Chris previously spoke out about the special ''connection'' he has with his new girlfriend, Karrueche, and how he would like to marry her one day.

He said recently: ''I dig her, I dig her man, She's dope. I feel like especially being in this industry you need someone that understands you and understands who you are personally except for your name.

''You don't have to be buying them bags, let me stunt on you right quick. Although I do it because I love her, but that don't come with the territory, at the end of the day we have a real connection as best friends on top of our intimacy.''

When asked if he would marry her one day, he added: ''Yeah, man, but like I'm scared of marriage because I'm young right now. That's the only thing that ...''