Rihanna reportedly feels "vulnerable" following the backlash about her romance.

The star has reunited with her ex-boyfriend Chris Brown, who assaulted her in 2009. Due to the volatile nature of their relationship she has been criticised by some for taking him back, although she has remained defiant.

The two stars appeared in love as they say next to each other at the Grammy Awards this year, but she was apparently bombarded with hateful words as she entered the ceremony. People shouted at her for getting back with Chris and it reportedly left Rihanna worrying about her decision.

"Rihanna used to feel invincible, like she could do anything and people would love her, but now she feels vulnerable and under attack by people who are angry that she's back with Chris," an insider told Heat magazine.

The star opened up about her relationship to Rolling Stone magazine, the first time she'd admitted the rumours she was dating Chris again were true. She insisted he has changed and said he knows he can never do anything to hurt her again.

It's been suggested the star expected people to understand her side of things and has been left dismayed by the criticism she's received.

"She got such a scare," the source said. "Chris has told her it'll blow over, but her management have expressed concern. Now, she can't help but think twice about the relationship."

Chris attended Sir Elton John's annual Oscars viewing party last weekend, during which he opened up about his romance.

"We are back together. She is the most beautiful girl in the world. But I'm sad she couldn't be here tonight; she is rehearsing for her tour," he said.