What's worse? A private lap dance or his subsequent behavior? It just screams suspicious. Carefully looking elsewhere so he'd avoid your eyes, the pathetic attempt to play dead, the refusal to answer when you moved past that nonsense. He says nothing inappropriate yet won't give a straight answer as to what went on? A private lap dance might be the least of your concerns when one wonders what else went on back there. You need more, you need honesty and openness and no more bullshit evasion. Don't proceed with anything on the marriage front until you get all of this, and even then, don't proceed with anything unless you're well satisfied with the answers he gives you.