Should I tell her?

J • 30 | 🇨🇦 | 🧡 | ✈️
So I recently moved cities a couple months ago and met some new people. I met this guy and we hit it off almost right away, he was charming and funny and seemed very much into me and interested in my life. We would flirt a lot when we were around each other and when we went out for a group beer I ordered water because I was broke and he paid for a couple drinks for me. He said he wanted to buy me another one sometime and take me out. I was of course exstatic so I said yes. So as most women do I creeped around for his social media pages and I found his Facebook. I looked through a couple pictures to make sure it was the right person before adding him and there were multiple pictures of him with the same woman. So naturally I got curious and looked at her page. They're married. I was shocked. I didn't see him for some time after that but never brought it up- I didn't know what to say. So the next time I went out with friends I had probably a couple too many drinks and he showed up. At this point I basically forgot/wasn't thinking about the fact that he was married so he offered to drive me home and we made out in his car. Nothing too R rated, but nonetheless making out and his hand was touching my thigh. We didn't sleep together or anything but as soon as I got some quiet time the guilt really consumed me. 
This is the part where I ask you guys to please not judge me, I have ALWAYS prided myself on not being "that" woman and the judgement I put on myself after this is probably far worse than anyone else could make me feel. I've been cheated on, I know exactly how it feels and I feel shitty for the part I played in it. When I was cheated on another girl (stranger) who witnessed it actually came to me and told me herself what happened. I've never been so thankful to a stranger for their honesty and I ended that toxic relationship. Then again I was t married.. My question is should I tell his wife what happened or keep it to myself? Should I not tell her and talk to him instead? I need advice!