I (36M) stuck in a cheating situation with sister in law (38F). I don’t know how to end or save my 15 years mariage with my wife (40F)

Hi,
So long story, I am married since 2015 to my wife. She has two youngers sisters and I have always had a good relation with all his family and helped everyone around their house or anything.

Last summer, her sister which is also married wanted to change the floor in their house. Her husband is not really good with it and I offered them to help instead of them paying someone to do it. I had no intention other than help them but that is where my problems started.

For a couple days, after my work shift I went to their place to remove the old floor. My sister in law is working from home and was there. The first 2 days, I work for 1-2 hours and came back at my place for dinner etc.

On the 3rd day, I went and my sister in law told me she had to leave for an appointement so I stayed alone at their place. As I went in their bedroom to remove the floor, I saw on the night table a dildo and a vibrator. On the bed, there was a cute matching thong and bra. I kept working but started to think about my sister in law with it or playing with the toys. I have never think about her before and we never flirt or anything.

Anyway those ideas made me super horny so I went in the bathroom and jerked off. I then finished removing the floor for that day and left home.

The day after, I went to their place to work. Sister in law was still there. At some point, she called my name. I went to see her and she was calling my name from her bedroom. I went and she was wearing only the thong and bra I saw the day before. She was smilling at me and grabbed my hand. She put it on her pussy. I tried to back off but she prevent me.

I was very uncomfortable in this situation. She started to touch me over my pants and said she saw me jerk off the day before. She said they had a camera in the bathroom (wtf ??) and she saw everything.

She told me she was thinking about telling it to my wife or not. She was still touching me saying that and unzipped my pants. I wasn’t able to move or anything. I felt like I had to let her do what she wanted or she would talk to my wife.

Anyway on that day she sucked me and asked to be fucked in doggy. It took me a very long time to cum because I was so uncomfortable. I am not the kind of guy who cheat or flirt with other girls.

After that day, I decided to finish the floor on the weekend while her husband was present. I was feeling guilty and very bad about that situation but my sister in law wasn’t at all. She was making little smile at me all the time and was more invasive.

A month or 2 later, we had a family dinner at my mother in law’s place. I went downstairs to grab chairs for everyone. As I was downstairs, sister in law showed up and came very close to me and started to kiss me.

I stopped her and pushed her away but she told me I should let her unless I wanted her to tell everything to my wife. I felt like I had no choice. She kissed me and went on her knees to suck me. I was afraid to get caught and didn’t took long to finish. When I went back up with the chairs, my wife asked why it took so long.

Sister in law said she was showing me some pictures of their childhood. My wife trust me and know how I am so she didn’t make ideas with that.

Since that day, my sister in law is very controlling with me. She finds reason for me to go at their place and once there she use me for sexual reason..

Recently, she seems to always want more and it is a weekly thing. I want to stop it since the first time but I don’t know how.

I never wanted that but if I talk to my wife she won’t believe me and will divorce me.

I need some help or advice, what would you do in my situation ?