Sister Dearest

I'm Reg. My parents are both deceased and I have only have a sister Grace no other close relatives I returned from aboard 7 months ago and got a 1 room apartment. I'm 27 and 5'11" 98lbs. I play sport a lot to keep fit, I'm no superstar far from it. Just as I moved into my apartment, I received a call from my sister Grace 29 5'4" 57lbs nice body and worn thick glasses. She asked " Could she stay with for 3 to 4 weeks as she was moving here for work and to have surgery to fix her eyes. So she wouldn't need glasses, She was getting 1 eye done the following Monday and the other the Monday after that. I said " ok, I will sleep on the sofa and she could have the bed". She said " She would have the sofa as she was shorter". I said " I usually slept on the sofa anyway, but we can work what to do later". Grace is a doctor and was going work at the General Hospital after her surgery. On the Wednesday morning after her surgery, I got up early from the sofa and went into the bathroom to masturbate. I was sitting on the toilet and was caught by Grace. She walk in her PJ's, she looked at me and smiled and then started to brush her teeth. I stood up and was about to leave, when she said " Don't let me being here stop you. Finish what you started. I said " I couldn't". She said I will help". With that she took off her PJ's and started play with herself. After a couple of minutes we were playing with each other and finished up in bed together. She said " I'm Bisexual and anytime your horny, I will be happy to help you out. Three Weeks later she started at the Hospital and a week after that, I came home and found her bed with a nurse called Karen 24. I was about to leave when said "We been waiting for you, you want to make threesome?" Ok was my reply, we 3 have been together ever since. Karen is pregnant and Grace also is talking about having a baby by me. We looking for a bigger apartment or a house.