Drunk, and about to commit sin..with wifes mother?

answer me fast. i've always been into my mother in law. Shes 54 with a body 30yrs younger. i'm 28 and married to her 30 yr old daughter ....for money...sorry. My wifes away for next two nights. i'm with mother in law who is flirting and wearing a tight top. I'm on pills to help me...down there. so I'm feeling the vibe. Shes upstairs washing herself down and getting into something more flimsy because the house is warm. Shes told me that she finds it hard to wear so much clothes. If she keeps flirting and makes a p...will it be forgotton after one night of fun and alot of awkardness at her grandaughters christening in two days time? bare in mind her husband hates me but is out with his mistress...so my mother in law says. Is this a tail for disaster?