If he's directly at fault for making your face leak, he's probably thinking, "Initiate apology protocols! Update meta-motor cortex parameters, and reroute primary emotional algorithms through the positronic matrix! Set all behavior directives to "I'm sorry, baby," and await command!"
He's also thinking "Crap!" And "Beer!" He could also be thinking "I broke it, I bought it." I'm assuming we're talking about real tears. The guy said or did something that disappointed you or hurt your feelings. Because, let's be honest here, women cry as much as men don't. Some women cry to get their way. They use tears as weapons or bargaining chips. You've heard the tale of "The Boy Who Cried Wolf," right? Believe, every guy has dated "The Girl Who Cried."
If the guy is to blame and capable of taking any responsibility for his actions, he is feeling regret. He is thinking "This sucks. Seeing someone I love in pain hurts me in the bio-mechanical ball of meat that pumps my blood."
Men aren't as emotionally nimble as women. When it comes to emotions, women are like the beautiful, graceful gazelle that can gallop and weave, and make hairpin turns at high speeds. Men... we're like Rhinos. The tears will freak him out. He might look at you like you're suddenly the most fragile being in the universe, a woman made out of Pringles. But if he has any self-awareness, once his programming has reached it's logical conclusion, he will apologize and try to make amends, as best as he can.