Lonely Sister in Law

I'm Patrick 39 married to Cheryl 37 and we have 2 children and both have great careers and decided to limit our family at 2 children. I've 3 siblings and Cheryl has just her sister Chelsea 34 single and great career also. At the last Christmas gathering of their family, I saw Chelsea looking depressed and not wanting to get into her personal problems asked Cheryl. She told me she tell me later and I left it at that, later on at our home and children in bed. Cheryl told that Chelsea was lonely and wanted to start a family of her own. The trouble was Chelsea is a perfectionist and she had scared every man around her away. I said tone it down and see how that works, Cheryl said she already tried that and that scared them even more. I asked so she going to do IVF or something like it, no to many legal problems and health problems for a single woman to content with. So that why she depressed I asked. It was, but we have found the answer thanks you she said. Me what did I say I asked, you didn't say anything except you also showed concern for Chelsea Cheryl answered. How does that fix her problem I asked, simply you get her pregnant and she can have her own child she told me. I was totally shocked and finally asked who came up that idea, I did Cheryl said. Why me I asked, your family, not a blood relative and you were concern for her wellbeing and it won't cause legal issues she said. What about us I asked, no problem it won't be behind my back and we could have threesomes she said. I was stunned and in the morning (Sunday)I was still a little bit stunned. When Chelsea turned up. Cheryl and her talked and it was about me as they kept looking up and at me. Finally Cheryl asked me had I made up my mind, I said I wanted to help Chelsea but didn't want to risk my marriage. Meaning I hadn't made up my mind it, but said great I get mother to take the children this afternoon and we can get started. I was shocked and asked your mother knows about this, no she doesn't its easier to get her to have take the children she replied. I felt it was all decided and let it go at that. That afternoon children with their grandparents, I was to fuck my sister in law to get her pregnant and with my wife helping us. It was awkward at first but we had a all in sex secession and I got to fuck both Chelsea and Cheryl and had to pull out Cheryl and deposit my sperm into Chelsea. Then I heard Chelsea apartment had work being done on it and she was moving in with us till the work was completed. A sudden renovation and their accept that our place was closer to Chelsea work than theirs. Chelsea joined us in our bed and regular sex followed. I did succeed in getting Chelsea pregnant and as a result she sold her apartment and is living with us fulltime. One other thing unplanned for happened Cheryl got pregnant also. Which was explained by having threesomes and getting so hyper aroused that you forgot to watch where you leave your sperm. Yes that's right I got the blame and it wasn't her wrapping her legs around that caused her to get impregnated. But all's good that are happily pregnant together, only there mother Janet knows who the father of Chelsea's baby is. She is a keen observer and doesn't care that I'm the father as she says I a good husband and father.