Twin Trouble

So me and my wife have been married for 10 years and I'm not ashamed to say she is a hot twin so I love when her sister stays over. Me and her sister had a fling before I dated my now wife which caused confusion for people as they are identical except for the piercings. Anyway to the point, my wife and I decided its time for a baby so we stopped birth control and hurray we're now expecting downside they decided to share me without telling me and her sister is now also pregnant by me. It's come as a bit of a shock but they have agreed between them that as her sister is staying with us during the pregnancy I can have sex with them both as it won't do any damage as they're both pregnant so I'm gonna enjoy the next 8 months to the fullest.