He's trying to keep a hot bod to keep his lady!

Patrick Schwarzenegger hit the gym in L.A. yesterday after spending the night at girlfriend Miley Cyrus' house, and the USC student must be trying to sweat out some of that spring break partying!

Arnold and Maria's son and the pop princess hit up Kiwami in Studio City for dinner on Monday night, so she must not have dumped him for getting handsy with bikini clad girls in Cabo! Not that the "Wrecking Ball" singer is all that pleased with his embarrassing antics, though! "She’s not happy with him,” a source told Us Weekly.

The 21-year-old should know that you can never keep secrets and get away with it in Hollywood. His dad having a baby with the housekeeper should serve as a good reminder to not make mistakes!