Two Famlies in One

I'm John 32 average looks and build, married with 2 children. My wife Beryl 31 has a Sister Kathleen 33 lesbian. Both are very good looking and are as close as twins. Long story short, Kathleen had broken up with long term partner Ruth and had moved in with us. Unknown to me Kathleen had decided to have a baby. Her and Beryl had also decided to keep it in the family. I was to be the sperm donor without knowing it, Beryl told me that would have use a condom for a couple of weeks as she had to go off the pill for a while. Nothing to worry about I was told, so I said no problem. I started to think it was better that she was off the pill as I was getting more sex from her. It went from once or twice a week to every other night. After sex she would remove the condom and clean me up and leave to get rid of the condom. She would return about 10 minutes later, saying I was great and we would cuddle up and go to sleep. A month after this started she said All is back to normal and was going back on the pill. But she may have to off it again if the test results were negative. She wouldn't say what test, anyway a couple of months later. Kathleen announced she was pregnant, I didn't know that she trying to have baby and wondered who was the father. I was told it was a donor and she all about his medical history and he was of good stock. About a month before the birth, I was told by my wife Beryl that I was the father and they wanted to put my name on the Birth Certificate and hoped that I wouldn't be upset about their deception. I was shocked at first, but was happy to go along with it. Adding that if there was a next time, that I be included in all. I would even be willing to have threesome with them. Beryl said In your dreams, but than you never know your luck.