Alex Pall of The Chainsmokers is eating one big ass crow after he was caught cheating on his now ex-girlfriend, Tori Woodward ... and he says he's miserable over what he's done.
We got the DJ Tuesday at LAX before he jetted off to Qatar for a gig, and we asked how he was holding up after Tori put him on blast last week for creepin' on camera.
Alex pours his heart out -- telling our camera guy his ex deserves a better guy than him.
He also explains what he's learned from all this ... and we're inclined to believe him.