We Worked Thru Issues

My wife of 14 years and I worked thru to a point of being happy with each other. We got married during college because we couldn’t focus on education unmarried. We were very sexual in our relationship. We graduated and started good careers. Married six years at the time we had two children. I got a call one day that my wife had been having sex with a coworker. His wife discover the affair. They had been having an affair for five years. He quit his job and my wife got his position. I confronted her with many discussions. I told her I wanted paternity test and if he father either kid I would divorce. She said she already did test and showed me the results and I was the father. She admitted to letting him cum in her unprotected but my sperm won out. We stayed together and we continued being very active with our sex. Three years later her younger sister needed to stay with us just after having a baby. Her husband had reserve duty for four weeks. Her sister would breast feed her baby in the open feeling I was close family. My wife joked with her saying milk breast was my weakness and I would want some. The next day my wife hadn’t come in from work yet I watch her feed her baby. She jokingly asked did I want some. I surprised her and came over and pulled out her other breast and massaged it. While doing so I put my hand between her legs and started frigging her. My wife arrived so I moved away from her. That night I was quietly awaken by my sis-in-law. She took me by my hand and pulled me to the quest room. She gave me a quick blow and got on top of me. She wouldn’t let me remove her shirt embarrassed about her stretched stomach, but I assured her that is what makes moms beautiful. It wasn’t long we cum together. She was apologetic but after a rest I got on top of her and did my best to make her sore and cum inside her again. The next three days I came home on lunch breaks and after work when wife had kids I squeeze milk tits and empty my balls inside her. We took a two day break then Saturday came. We drove and visited their parents and left my kids with them. When we returned home my wife told me her sister confessed what we had been doing. My wife said she was going out so her sister and I could have our last sex session. I was sitting on the bed feeling guilty. When my wife walked out with a party dress on. She raised it up and showed me no panties and left the house. When my sis-in -law got the baby asleep we hit the bed. We had sex until we were exhausted. We both slept in our guest bed with waking up to attend her baby. My wife didn’t come home until the middle of the morning. She said she got with a guy and rented a room. They were to drunk to have good sex but tried. She left him asleep this morning and came home. She said no more flings for either of them or their would be consequences. We all acted normal until sister returned home two days later. The situation exist that her sister had a daughter 9 months later. I should have known she was ovulating by how aggressive she was for sex. Only the three of us know I probably fathered her daughter. My wife feels vindicated for her affair and is really happier in our relationship. I have been faithful but when we are at family gatherings I lust after my sis-in-law knowing how good she is between her legs. My wife really keeps a watch on me when we are together. We are still going strong in my marriage and parenting.