My mother-in-law and I go to a hotel to at ease, her husband doesn't know

This is my mother-in-law, we met since my girlfriend introduced us to her family recently, for some reason I realized that my mother-in-law liked me and little by little we were able to live more between her and me, I asked her for her number to be more discreet and a few days later, I told her that she was very beautiful and attractive, She told me that nothing could happen because she was with my girlfriend, but she also admitted that she liked me very much, a week later she started us to drink wine and we have been hard since then, she tells me that she had a lot of desire since she met me since her husband did not like her