Married because of One night stand

Short history: I was attending university and dating my now wife at the time, she was 18 and I was 19 almost 20. My family is quite wealthy and so is my wife's family. My wife's family was just her and her mother 37 widowed by skiing accident 3 years earlier. Plus, uncles and aunts and cousins no grandparents as they already had passed away. In my family I had an older brother and sister and both my parents, and both sets of grandparents plus aunts, uncles and cousins. Both our families are of the born-again Christian mind set and that why I'd had to marry. I'd hadn't actually had sex with my girlfriend and had been able to feel her up at times. Anyway, she went on a trip, and I was at loose end with her away for 5 days. My family were all busy and I was alone mostly and so dropped by to see my girlfriend's mother. Her mother had been drinking and was randy and she straight out asked me to fuck her. The one thing I wanted to do my girlfriend was fuck her and her mother had asked me to fuck her. Her mother was an older version of her daughter in looks and I agreed to fuck her and was awkward at first as it was my first fuck. But she had told me what to do and I really enjoyed the afternoon. The next day I returned to see if I could get a repeat. No, she was busy but asked me to come back and stay the night with her instead. I agreed and told my parents I was staying at a friend's house, and they were happy with that. No extra information required that evening I'd dinner with my girlfriend's mother and we had sex again several times and again in the morning. She was safe she said as her husband and her wanted another child and she never got pregnant again. Her husband had a test was shown to be able to father a child. So, she didn't bother getting tested believing it was her at fault. Well, she did get pregnant, and I was at first very shocked. But I was shocked even more when she said I'll have to marry her daughter. I thought it strange I marry the daughter who wasn't pregnant, but they have the same name, and it would look better in our social group. I was a little surprised her daughter agreed, but she and her mother were very close. The news that I had gotten my girlfriend pregnant shocked my family and they said I'd to do right thing and marry her. The family were okay with us marrying and it was arranged quickly in the next state. Now married and having sex with my wife and her mother also in the bed with us. I quickly got my wife pregnant and that put a wrench into the plan so to speak. But that was solved by saying she was to have twins. Albeit months apart, but a trip away for the births would solve that. My mother-in-law had a boy, and my wife had a girl, which was used to cover their size different. Now 27 years later I've 5 children with my wife (4) and mother-in-law (1). My wife's mother lives with us still and she checked with her late doctor about his virility test and no record of such a test was found. I'm quite happy about that, as it got me married to my wife sooner than it would've happened before.