Adam Levine ditched his shirt to join his bikini-clad girlfriend, Nina Agdal, on a grassy volleyball court during their vacation in Cabo on Saturday. The couple bared their bodies as they played a match against a group of friends. Once the game was over, Adam and Nina joined their pals for a dip in a pool. The trip marks the first time that we've seen Adam with his new model girlfriend. Adam and Nina started dating earlier this year, and sources say that the romance is "still new." These two are hardly the only new duo that have been heating things up in recent months — check out all the new celebrity couples of Summer to see who else is in the mood for love.