The couple previously dated several years ago when the then-teenage Rihanna was attempting to launch her pop career in Barbados.
Rihanna recently returned to Barbados for a vacation and reconnected with Sealy, a source told The Sun.
The two were seen spending time together at Rihanna's estate and later attending a carnival.
An insider added: "Negus has hardly left her side. He was her first true love. The ladies here all love him - they call him the Love God. They've hooked up in the past when she's been back in Barbados but now things have progressed into a proper relationship again."
A rep for Rihanna hasn't yet commented on the report.
In July, Rihanna was rumoured to be casually dating her 'What's My Name?' collaborator Drake.
Rihanna's producer Verse Simmonds has said that Rihanna is close to completing her sixth studio album.
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Watch Rihanna and Drake's 'What's My Name?' music video below: