The duo called off their volatile romance earlier this month and have been involved in a Twitter war and friends of Chris, 24, say he thinks they need some time apart.
A source told HollywoodLife.com: "It is what it is. One day he`s with her, and the next they fight and they`re over.
"He`s sad that she`s sad and it irritates him when she blasts him on Twitter. But that`s how girls are sometimes, he can`t help that."
"They`re giving each other space right now."
However, friends believe the duo - who split up after Chris was arrested for beating Rihanna, 25, up in 2009 before getting back together last year - will rekindle their relationship in the future. The insider added: "I`ll tell you this much, it`s never really done with them."
Following the split, Rihanna and Chris were embroiled in a bitter Twitter exchange, although they didn`t refer to each other directly.
Chris hinted the `We Found Love` singer had been unfaithful following reports she recently partied with her ex JR Smith.
He wrote: "`She`s not mine if she`s everybody elses." His tweet came a day after Rihanna seemed to take a shot at the rapper when she posted an Instagram photo featuring the words: "If I drop all of my hoes for you and we still don`t work out you owe me some hoes."