Rihanna and Chris Brown split and got back together again despite an assault, fights and rumors about Karrueche Tran. But this break up might be permanent for the former couple, according to Hollywood Life.

The "Stay" singer, 25, and "Love More" crooner, 24, just can't put their differences aside despite their infatuation with each other.

"They went through a lifetime together and they're only in their 20s," said a source close to both superstars. "They've had lots of ups and downs and then a HUGE down. Sometimes Chris can't even look at her because it reminds him of the s*** he did years ago. Even though she forgave him, the world hasn't."

The source continued, "That's the s*** that's f****d up. It still distracts him from the music and his life. It's always in his face and something he can't shake."

The world just can't forget Brown's infamous physical assault against Rihanna at the 2009 Grammy awards. The mistake has put a dark cloud over the "Fine China" singer, who has tried to rebuild his public image and move back into the arms of both Rihanna and Tran.

Recently, Tran and Brown showed their love for each other at the Orange County Fair in California on Sunday, reported HL.

[For fair photos, click HERE.]

The former couple rode carnival rides and looked very happy. In fact, their closeness in the photo suggests a strong friendship.

The baby-faced crooner even tweeted how much being friends matters in a relationship on Monday.

"How do you build a house without a foundation????" he tweeted. "Friendship brings the trust and love stronger. You have to like a person to love them!"

Tell us what you think of the latest on Brown and Rihanna's love for each other in the comments section below!