I want an affair with my mother in law

I've only know my mother in law for 2 years. Out of the 2 years I've been getting to know her recently. My fiancée is close to her mother and her mother is close with her. We have a daughter and we spend even more time with the mother. Lately my fiancée and I haven't been making love, due to the fact that she lost her ** drive with the pregnancy and other health issues. Me, I've been battling my ** drive with watching ** and that's not working. I'm like like a ** teenager but I'm 30 years old. My mil is in her 40's and hasn't been with a man for years. This is what I was told. I know she is lonely,**, and just wants that special kind of love that only a guy can give her. At first I didn't pay it any mind but now I'm starting to see things clearer. If I'm around I see her looking at me. I'll yawn, because if you yawn then the person looking at you will to, and she'll right along do the same. I've seen her on countless times not only checking me out, but also stirring at my package. I didn't think anything of it but then again I started to wonder. When she talks to me it's like she's lost of breath and she will look into my eyes then look away constantly. She'll sometimes hand me things or I'll hand her stuff and she'll touch my hands more in a scared shy but I want to way. We haven't had much time alone but when we do it's like beinging stuff done in the basement for her, or a job interview where she'll watch our kid until I get back. When I'm taking stuff into the basement she'll come down sometimes and be looking around at random stuff. Once I put what needs to be down there I start to walk back up and when I do so she'll start talking under her breathe. When I'm going to an interview I'll come back and I'll tell her how things went and she be back and forth from where I'm at to look out the windows. The reason she's looking out the windows I think is because her mother lives with her and she works at a certain time in the morning then comes back then goes back to work. And her to younger sons work but you know people can just pop up at any given moment. When it's just us we talk about random stuff nothing sexual. She doesn't drive so we take her to stores with us. Just recently, she was bringing up that a person was asked to go to a ** party and was like ewww but ended up going. I commented and said sounds like fun jokingly and my fiancée stated to her mother that she could never go to one with her and so did my mil. Mil said that she would need some drinks in her then she would open up when seeing ** toys and how to use them. Me I'm just lost for words and just not saying much. Mil and fiancée talked for 15 minutes about this. Mainly the mil was talking. When we got to the store in the produce section she picked up a big long cucumber and started laughing while showing us. Idk if it was directed towards me and it was ok to do so because her daughter was there I think. I'm thinking she did it around her with me so if did it without her around I may get weirded out and tell fiancée. Fiancée said mom what the ** are you doing and she just giggled. So being that I'm an attractive guy and I get hit on by plenty of females from different races and ages I go with my gut instinct and it's telling me that mil wants some action. I know the horrors and the bad that can happen if this is true. But like I said I'm as ** as any other person who doesn't have ** as much. I'll make love to my fiancée like 1-4 times a month and that's a deal breaker on my end. I'm not going to lie mil is short and curvey funny and beautiful, and I know that the kitty cat hasn't been physically touched by a guy. So I can only imagine what it's like. She is my temptation as of now, I'm thinking because she is the only other female that I am close with. I do want to dive in the poison but I don't want to be misled. And the worst happens. What should I do? I just want ** from her. No getting into feelings or falling in love. Help!!