My mother became Insatiable update

Katherine went to look after her sick and I went with her as my father wasn't willing to go. I looked after the chicken while she looked after her father Alfred, sadly old Alfred passed away and my divorced my mother with wasn't a concern to her and I had started having sex on the night of my 22nd birthday and have been sleeping together ever since. But she wants grandchildren and started looking for wife for me. No surprise that she wanted grandchildren but as she only had me due a miscarriage a couple years after I was born. Regularly allowing me to fuck her and also asking me to fuck her also, I had everything I needed a loving mother and lover all rolled into one. Anyway she finally found the perfect girl Shelly worked the doctor's office. She was adopted by a local couple as 5 year old and never done well enough to go to university. Both her adopted parents had already passed away during the pandemic and Shelly was living alone. As far as Katherine could tell Shelly didn't date, stayed home except when at work and done her shopping on the way home from. She also only lived 1 mile from town down the same road as our chicken farm 5 miles further out. Katherine started to befriend Shelly and also visiting her at her home, Katherine found out on her visits that Shelly collect unicorns and fairies figurines. Or as I called them on hearing of them dolls, but was quickly put in my place by Katherine. Anyway after a few weeks and a firm friendship, Katherine invited Shelly to Sunday lunch and she accepted. A few more followed and I was sent to pickup a new trailer, Katherine had bought online to replace the old rusty one we had for removing the chicken mature from their sheds. It was 5 hour round trip and Shelly came for lunch which was now regular and Katherine seduced her and they were still together in bed when I returned. I walked in on them, Shelly was shocked at getting caught. Katherine told me to naked and join them. Which I did and I took Shelly's virginity and sex between us 3 became regular as well. Katherine wanted Shelly pregnant and Shelly got pregnant and a quick wedding (March 2022) later. We all live together and sleep in the same bed and our daughter is due in late September. Shelly has sold her house last month, still works at the doctors clinic. Katherine is very happy and still insatiable as before, but if I'm not around she sleeps with Shelly.