Response To Secret Relationship with BIL

I went threw a period where I was working long hours and not home much. My wife’s little sisters boyfriend had basically moved in with us because he had no place to live and my wife’s parents said there was no way he was living at their house with their 16 year old daughter her boyfriend. Anyway I was working long hours and my wife and her sisters boyfriend liked to lay out at the pool and smoke weed. We eventually they got horny and my wife’s sisters boyfriend ended up fucking my wife. This was going on for a couple of months and I didn’t have a clue. My wife’s sister caught on to their messing around.
One weekend I was home and my wife and her sisters boyfriend was at the pool. Her sister came to the house dressed so damn sexy tight mini skirt and blouse she ample cleavage for a 16 year old. I could tell she was up to something and it didn’t take her long to let me know that she knew her boyfriend was fucking my wife. She wanted revenge on both of them. I was like what are you thinking about. She blatantly told me she wanted to suck my dick and me to eat her pussy and wanted me to fuck her. I wasn’t saying no to this fine piece of ass in front of me. She went and pulled my cock out of my shorts and started sucking my dick while I was feeling her up. I got my hand in her Dante pink lace panties and started fingering her sweet tight pussy. She was cooing and moaning and said she wanted me to fuck her. I said Yvonne I’ll fuck you after I taste that sweet pussy of yours. I went down on her head up her skirt eat her panties and pussy. She both hands on the back of my head thrashing her pussy all over my face. We got naked I crawled up on her getting ready to bury my cock in her sweet teenage pussy. She freezes and said do you have a rubber in like no why would I have one I’m married. She said fuck it just stick it in my pussy and I did. We fucked missionary doggy and her on top riding my cock.
I finally rolled her on her back and fucked hard missionary style
I felt the pressure building and knew it was getting close my balls were tightening up. I told her I was about to cum and she cum in me I want to feel it pulsating inside me. I unloaded in her unprotected pussy. Six weeks later she announced she’s pregnant and her boyfriend thinks it is his.