Then This Happened

A few months ago our wives were in France for a few weeks so my father-in-law invited me over to dinner. After several bottles of wine I found myself dressed in my mother-in-law's sexy lingerie, fully made up, stockings, heels, and wig, the whole nine yards. He took several pictures, including my ruby red lips wrapped around his big cock. He fucked me up my ass and came inside me. It was thrilling at the time, but now I'm utterly ashamed and embarrased.
He made it very clear that it would be our secret as long as I complied with his wishes. I work for him and we travel together for business. While away, after business is concluded for the day he has sent me back to the hotel to get dressed for him a few times. He has implied that I may be required to satisfy some of his friends and customers at some point.
I don't see a way out of this predicament.