My family inheritance

I'm Greg 24 until early last year single, my great uncle Andrew on my late father's side of the family died and as his only living relative I inherited his entire estate just over forty acres with a 5 bedroom house and a barn and some livestock. The land was an entire island set in a lake and it away from most of the populated areas near the lake and had been off limits to people for years. I myself hadn't ever been there, my mother had also passed away when I was only young and I lived with my father until his death 5 years earlier. Then I had already left school and trained as a carpenter and rented a small house. I had heard of great uncle Andrew, but had never met him, even those he only lived 35 miles away in a straight line on his island. At the same time I was out of work and the building industry in the local area was dead. I had accepted a job at the lakeside town only 10 miles from the island and thought I would live there. But I had a few things to take care of first. My late mother's sister Ruth 42 and her daughter Robyn 19 as far as I knew my only living relatives were living just outside the town also unemployed due the mill closing down. I used to their place for Sunday dinners and we were very close. They were also renting and with not much chance of work in the area I asked them to move to the lakeside town and told them they could stay with me until they got what they wanted. Ruth and Robyn accepted and we headed off to the island and we found a house that needed a good cleaning and some updating. Ruth and Robyn spent 3 days cleaning it top to bottom and threw out a lot of rubbish. I burnt the rubbish in a big hole and after using the old tractor on the farm pushed dirt over it. Jobs for Ruth and Robyn weren't available at that time and they contented themselves looking after the farm and I worked in the town at my new job and started doing repairs and improvements to the farm on the weekends. I would take both Ruth and Robyn into town for nights out dinner and a movie. Nothing much happened for a couple of months and then Robyn caught me masturbating in the barn and took over stroking my cock. After a couple of times doing it together we had sex for the first time and about the fourth time I was fucking Robyn, Ruth caught us both and at first she was upset. But then decided to let us continue, at first she left the barn but returned shortly after and sat watching us playing with herself. Robyn asked her to join us and Ruth answered no, but then changed her mind and suggested we go inside and continue it there. We all went inside and I fucked Ruth first and then Robyn again. During the next week I ordered the biggest mattress I could and bedding for it and got some lumber and made a bed to take it. Two weeks later the mattress had arrived and we all started sleeping together every night and due to regular sex Robyn got pregnant and as far the anyone outside our family knows she is my wife. Ruth takes precautions and says it is unlikely she get pregnant due to her age, but take precautions just in case.