Although no one agrees, I still think him having a lap dance (against his wife's wishes) and then lying about it constitutes a serious breach of trust. She didn't kiss an ex, she kissed someone she just recently connected with and although it wasn't a great choice, I still think it was done in retaliation and probably meant nothing.
She was probably feeling very betrayed and who can blame her. Lap dances do come with an amount of shared intimacy that should really be reserved for inside of the marriage.
I hope the marriage can be saved and nothing but complete disclosure from here on out should be required from both parties.