Got my girlfriend's mother Pregnant

It was case of me being in the right place at the right time. I was 20 at the time my girlfriend was 18 almost 19, her mother was 38 and a heavy drinker. Started drinking after her husband died 2 or 4 years earlier, I was dropping off things, my girlfriend had bought. She had dance practice, so as I'd to pass her home I would drop them off. Usually, it was the weekends her mother got drunk, but it was the anniversary of her wedding to her late husband, so she got drunk. In her drunken state she thought me to be her late husband, one thing led to another and now she pregnant. After she had sobered up, she realized it was me she'd fucked. No problem till she got pregnant, in our social circle a woman getting pregnant out of wedlock was really looked down on. Bad enough being a drunk, her daughter knew of our sexual act as she had gotten home and caught me getting dressed. But as her mother was happy for the time since her father's death, she accepted it as being necessary. With her mother getting pregnant, me and the daughter quickly married would pass off the child as ours. Problem 2 my wife got pregnant rather quickly. Her claiming her mother baby as hers would be harder with another baby bump still visible. So, we went away for 8months, coming back with "twins'. Fortunately, her mother had another daughter and my wife a son, easy to pass off the different in their sizes to them being boy and girl, boys are always bigger. Now 8 years later and 3 more children, we're all living together and quite happy with life choices. My mother-in-law also likes to have sex with us in a threesome, usually just once a month.