Drunken Party

I'm married and have 3 children and very soon another child will join our family. Except it's not with my wife it's with her only sibling, her older sister. Her sister had to go to some award dinner and her boyfriend broke with a couple months earlier and she hadn't yet found another boyfriend by the time the dinner. So, my wife decided I should go with sister as I knew her very well and could be passed off a boyfriend. It also happens that my wife and children would away that weekend visiting my wife's old school friend on her friend's birthday and celebrating it with her new wife. The dinner was great, better than I thought it would be. The alcohol flowed like a river and my sister-in-law was drinking and so was I. I don't remember too much from that night except the early part and the awards being presented and then starting drinking with my sister-in-law. We woke up in bed together totally naked and she got pregnant, my wife thought it funny and told her sister that she had been fucked by a great stud. But her sister said there's a slight problem, I've not been taking any precautions since my breakup my ex-boyfriend and your stud might have gotten me pregnant. My wife stopped laughing and thought a minute or two and said it'll be alright. Alright if you want your sister to get pregnant to your husband, then it was perfectly alright. Now months later my sister-in-law lives with us and share our bed with my wife and me. I'm the only one that still feels a little awkward fucking my sister-in-law with my wife joining in our three-way sexual relationship. But I do like the sex.