Chris and Rihanna, who first split in 2009 after Chris assaulted her, rekindled the romance seven months ago, but have been plagued by rumours of arguing and break-ups since.
The final straw is said to have come last week when Rihanna discovered Chris had been partying with his ex-girlfriend model Karrueche Tran.
The 25-year-old has allegedly raised concerns that she is not handling the end of the relationship well, and has reportedly dropped two dress sizes.
"Pals have told Rihanna not to get upset about Chris and Karrueche. They think the best revenge would be living well and looking good, but so far Rihanna's answer has been to party the pain away," an insider told British magazine Closer.
"It's understandable that she'd want to escape her feelings on this but she's taking it way too far. Everyone around her wants her to get some help - they're genuinely worried about her."
The Barbadian beauty is known for her outspoken manner and for enjoying wild partying sessions. Friends say the fact she is travelling around with her Diamonds world tour only heightens their concern.
"She's not in a good place and looks like she's self-destructing. Her friends are really worried about her and think she needs to take time out to detox and refocus," the insider finished.
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