Whining Sister

My sister Eve 23 was always whining that life was passing her by, I'm Greg 25 and I work as a plumber. I still live at home with my widowed mother Mary 47 and Eve, Donald our father had left years ago and we haven't heard from him since. We had the house and Mary worked 2 jobs seven days a week to keep it. I left school and became a plumbers assistant and went on to become a plumber. With me helping with my wages we paid off the house last year, Eve was always wanting things we couldn't afford and to go to concerts and on trips like her friends. I went to work came home and was happy to help Mary with everything and didn't complain. I didn't go out much at all and Eve was always going out with her friends and wanting money for things. I've been fucking my mother Mary for years and it started when she caught me masturbating and she joined me on my bed. We have kept each other happy ever since Eve was always whining about not have money to anything she wanted and I had enough just before Christmas and told her to get a job and earn the money she wanted. Eve isn't a work loving person and that made her cry. But then a band was coming play in our town and Eve wanted to go so badly, but the tickets were so expensive. I had more than enough money to buy her a ticket, but I couldn't see the value of spending so much money on a ticket. Eve told if I bought her a ticket she would sleep with me, I replied I could buy more than one fuck with that amount of money at least 3. With that, she offered to let me fuck her 5 times while Mary was working. I accepted and got a ticket to the band and Eve and I fucked 5 times and the condom broke while I cumming on the third time. The fifth time I was up to my nuts in her when Mary came home early and caught us. To Eve's great surprise Mary joined us in bed and we had a threesome. Eve has missed her period and we are waiting to see if she is pregnant.