Rihanna -- New BF's So Mysterious and She Loves It Like That (TMZ TV)

There's no mystery about why Rihanna and soccer superstar Karim Benzema are hooking up -- they're successful, attractive celebs ... why no?

The puzzling part of this relationship is why they keep acting like they're NOT in a relationship!! Sorry, RiRi ... we all know already. Maybe she's just in to that kinda thing.