After many years away

I left school at 16 and soon left home as well, my father and I didn't on at all, and mother passed away when I was 12. I had a sister 4 years younger than me, but we hardly got along at all. She was daddy's girl, I got by working low paid jobs and then met old Pete who with his wife Sam (Samantha) taught me and I started working with them and we went overseas for better paying jobs. As the years passed, I got more qualified and started earning really great money. Learnt a few things that Pete and Sam never taught me along the way. Pete and Sam decided they had enough and returned home to retire and I stayed. I liked the money and fun that came with it, I got a local pregnant and started a family. She gave me a son and I was settled for the first time in a very long time. But my wife got ill (cancer) and passed away when our son was 13, the fun of being away dimmed and then disappeared altogether. My son is quite smart, gets it from his mother and after he finished his schooling and was ready to go to university we returned home. I had him registered as a citizen at his birth and so it was simple getting him back home as I say. All the paperwork long completed, on getting back I decided to contact my family and found out my father had passed away 12 years earlier. But thru an aunt I found my sister now in her late forties and she was quite happy to see me also. I bought a house in the same town as the university my son was to attend. My sister was divorced no children and working as a bookkeeper. She was looking for another place to rent as her current place was being removed for enlarging a carpark near a mall. As I had 4-bedrooms 2-bathroom home, too large for me and my son. I had my sister move in with us, but I had the thought she could do the cooking for us better than I could. I would go away for work, and I knew my son had someone to look after him. He was doing great at university, and I came home, and my son was going away for an interstate sport competition. So, it was just me and my sister for a few days and I took her out for dinner and show. We really enjoyed ourselves and had a little much to drink. Ending up fucking after getting home, of course we knew it was wrong. But we really enjoyed the sex and as she was past having children. We continued fucking and still do today, I installed a connecting doorway to her room. My son hasn't noticed, or if he has didn't mention it at all. My sister is now my wife in everything except actually marrying.