He's left the Batcave!

Ben Affleck looked quite glum as he finally emerged into society amid reports he had an affair with nanny Christine Ouzounian, which he's denied.

The actor took a spin on Sunset Blvd in his muscle car on Thursday and looked less-than happy to be out in the world. Someone looks like a Sad Sam! And we can't blame him either -- we'd be pretty upset if we got caught cheating with the help!

News broke last month that Affleck had an affair with Ouzounian, who was only employed in the Garner/Affleck household for a few months but the relationship quickly turned into something sexual. Multiple sources claim that the nanny is in love with him and then his estranged wife is furious with the Oscar winner for the whole ordeal.

The Gone Girl actor has denied that he had any such involvement occurred -- but what else is he going to say? "I'm an idiot and I screwed the nanny?" Probably not ... at least not yet. We've seen these cheating tales before -- deny, deny, deny then come clean in a big, tell-all interview.

At least Jen isn't faking her own death to get back at him ... yet.