Leather and Bound Christmas

Will the Christmas Party that Luca planned bring Ethan and Luca closer together where they can get married, or will it tear them apart when Ethan brings along a friend? Where will that leave Luca especially since Ethan has been missing in action for a few days, and there was no text or phone calls from him. Whenever Luca makes queries concerning their wedding, Ethan shuts down. What is Ethan hiding? Is there something about Ethan that Luca will discover at his Christmas party which will leave him in shock?