Mom- IN - Law

I was visiting with my mother in law for a few days on my way to my home town. The wife had to work that week and said to pass through her mother’s town without popping by would cause hurt feelings. My MIL is an attractive 49 yr old. The second night there her and I hit the booze rather hard. Dirty jokes, sensual speak and some tickling led to an embrace and sex. When I’ve had enough alcohol my dick gets hard but numb. I fucked her forever bringing her to more than one orgasm but was unable to cum myself. When we awoke in her bed late the next morning she played with my cock then gave me oral until I came. As she put it, “it’s only fair.” That night she insisted I sleep with her. “I want to spoon.” We spooned but soon enough we were once again going at it. The following morning I was gone. What is said, will not come from me. I have never had sex outside my marriage or ever imagined having and certainly not with my MIL. If my wife finds out it will be through her mom and I can’t see that happening. Or can it?