My stepbrother David

I'm Adelaide 22 and my mother Karen 39 married Douglas 54 (decreased car accident) his only son David 31 inherited everything from Douglas which isn't a problem for Karen and me because Douglas had setup a trust fund for us before his death. Douglas was always working and always travelling here and there. Karen and David had started an affair and were in bed together when they received the call on Douglas's death. After funeral they kept there sexual relationship quiet from everybody. Then a Karen got pregnant to David and I was already included in their sexual relationship. It started as a cover for Karen and him being always together and Karen passing it off as David and me were in a relationship. I'm a bookish type and don't date and attend the local university and live at home with David and Karen. David took my virginity before Douglas passed away and I've been a regular sex toy for him since. I don't mind I really enjoy the sex and leave to him to take precautions and he decided on Cheryl getting pregnant. I should get pregnant also and as of last week I'm officially pregnant. I'm marrying him next month Cheryl want it that way. I just go along with them.