I took my pregnant sister in

I lived alone until my sister needed a place to live as she got pregnant and kicked out of home by parents. As my only sibling I thought it was my duty to help her, my parents claim to be Christians and that's why I left home years earlier and made my own way ever since. I don't see them or have any contact with them still, my sister was used by the minster and got pregnant, and my stupid parents took the minsters side and blamed my sister for everything. Not willing to get rid of the child, she had nowhere else to go but to me. Then the lockdown started, and I got horny and only had my sister living with me and she was already pregnant and couldn't get more pregnant. So, I got her to sleep with me and now years later we're still living together. She had a girl from the minster fucking her and we are raising her as ours. She still sleeps with me, and we've moved interstate and act as a married couple. She has gotten pregnant again and the baby boy is due next month, all test show no problems.