Mother's Family History Mess

My mother was adopted at the age of 1; no details of her family were given by the agency. Also, the law at the time didn't allow any details to be given out either. My mother was very lucky to be adopted by the people who did. They were wealthy and very caring, and gave her a great future. Fast forward 19 years: my mother met my father, and they married. His family was also wealthy, and DNA searches weren't a thing yet. They had me within their first year of marriage, and three years later, my sister. When I was 24 and finishing college, I got access to my trust fund, and so I started a small side business. I would mainly be working for my father's family business. My side business flourished, but not enough to leave the family business. I did employ several staff, however. This is where my story of incest started.
Unknown to any of us at the time, my mother's birth mother was 15 when she was born and taken months later into the state care and adopted out. Later on, when married, her mother had three more children, two boys and a girl, all to the same father as my mother. None were told of an older sister taken by the state. The youngest was born when her mother was 39, and her mother died 12 years later. She grew up living with her father till he died when she was 19; her brothers had moved on and never stayed in touch. Two years later, she started working for me in my side business. She was shy and kept to herself mostly, did her work, and went to the room she rented, didn't date. I didn't know of our relationship, nor did she. I was 27 and not in any relationship at the time, and I couldn't keep any going for very long. I was too distracted by my career and side business. I needed a date on short notice and was at my side business when notified. My employee/aunt was the only one there. The others were out delivering or picking up. My aunt was the office girl and the only female I employed. She looked okay, and not wanting to chase up another woman, I asked her to accompany me to the wedding of my sister, brought forward due to the failing health of her grandmother-in-law-to-be. At first, she wasn't keen, stating that her clothes were not good enough to attend such an event. I said I would get you the clothes needed. So, she agreed the next day, and so I had her made over and clothes bought. The following day was the wedding, which I did say was short notice. I took her to the wedding, and she stayed as close as a shadow to me. Barely talking, except when she answered a question. My mother was attracted to her straight away, and said she was a very nice girl, and insisted she come to the family lunch the following day. It was a part farewell for my sister and her husband going away on their honeymoon, and the usual Sunday lunch we all gathered for. My two grandmothers also took a great liking to her, and so I had to bring her with me or be in trouble. So, the next day we attended the lunch and of course the family women made more arrangements to see her again nd again. The main reason they wanted me to be married and thought she was perfect for me. It was the seventh time we were out together that I bedded afterwards. After the fourth outing, I had her move in with me, as I was getting very attached to her myself. Now, lovers, things progress quickly, especially when my mother rang early in the morning, I was showering, and my girlfriend/aunt answered the phone. As far as my mother and grandmothers were concerned, we were engaged, and I proposed. I was actually thinking about it anyway. Once married, a small family wedding, her brother's couldn't be located. My wife quickly got pregnant while watching television one evening an ad for DNA testing to find unknown family members came on. My wife asked me to get her the test as she wanted to see if she had any other family. I agreed and got two tests, as I wanted to see if I had any also, already knowing my family history. My wife and mother's lost brothers didn't turn up, or anyone else, but our family relationship did. After a family meeting, it was decided to accept the status quo. My soon-to-be-born son was very healthy, and at least it gave my wife the larger extended family she wanted.