I married my Step Sister

My father Jason married again after the death of my mother 2012 cancer she had a 5 year battle and the cancer won. My father Jason was with her the whole way thru and was almost destroyed by her death. Then in 2015 he met Grace widow and she had a daughter Marilyn and in 2016 they married. In 2020 Jason was killed in a work accident and I was left with Grace and Marilyn. Jason was well off money wise having inherited money from his parents and I had a trust fund setup by my grandparents on my birth, they have since passed away. So has my mothers parents in 2006 car accident followed month later by my mother getting cancer. Both my parents were the only child of their parents who also had no siblings. Grace and Marilyn are the closest to family I have left, I still lived with both at the time of Jason's death and stayed with them ever since. I'm Patrick 26 finished university and started a career, also being around Grace a great deal. I got really close to her after Jason's death and in July last year we slept together for the first time. It just happened and I don't regret it at all, it was just for our mutual benefit. Neither of us were into dating, Marilyn was away at university and over the Christmas break she and I started dating and also started fucking. Marilyn 22 has gotten pregnant by me and I asked her to marry me, she already knew I was fucking Grace 39. Who has now missed her last 2 periods and may also be pregnant to me. Which doesn't worry me as we all continue to sleep together, now that we've moved closer to the university Marilyn goes to. Which was prompted by me getting a transfer to be closer to Marilyn. We had a big party on setting up the new house together. We had a threesome and it's my be the reason Grace may be pregnant. Anyway Marilyn and I are marrying shortly and she will continue her studies and Grace will look after the baby or babies if she herself is pregnant. We are quite happy with the prospect of her getting or being pregnant we don't take any precaution anymore.