Experience with my mother in-law

Okay well I'm a 20 year old male and I'm verry verry sexually attracted to my 37 year old mother in-law, I'm always looking at her when I get the chance to, she has amazingly nice breast and a small plump ass.

Every time I'm at her house she wears a white undershirt with no bra on, last time my wife noticed me looking at her mom's boobs and got upset with me going on to ask her mom if she had ever noticed me looking at her in that way before Wich kinda put me on the spot at that moment. My mil said that she had never noticed me looking and that she was an "ugly old lady" so maybe i wasn't looking.

Fast forward to the day after that, I sat alone with my mil in the living room while my wife was using the restroom. I tried to avoid conversation with her because I felt awkward for the situation the night before, she ended up breaking the silence with "so..... We're you really looking at me the other night or was my daughter just going crazy"
I said "in all honesty I was looking at you, you are a beautiful lady I'm sorry if you felt dis respected by me" all she had the chance to say was " don't worry about it" before my wife walked out if the restroom.

A few weeks later my mil was washing dishes in her kitchen , I was going to throw something in the trash. The kitchen is small so I said excuse me and went by her to throw the trash i faced my penis toward her ass, when I was behind her she dropped one of her wet hands and grabbed my penis through my basketball shorts... I stopped and let her feel it, I was mainly stopped because I was in shock lol she then put my rock hard penis up against her ass, she was wearing skin tight leggings. I was still in shock but totally hard for her. I pushed my penis up against her soft ass and realized that we were in the kitchen and her 6 year old son was sitting near by in the living room watching TV. So I let her know that I felt a little awkward because her son was near us and I didn't want him to tell my wife so i went to the restroom to beat my meat thinking about having sex with my wife's mother.
Sadly that was the last chance we had to be alone.

Now we are only around each other when we all go out to a restraunt because my wife decided to move in to my house, now I'm debating on showing up while my wife is at work and her son is at school to continue what was left unfinished or to just forget about it...