My Special Relationship

I'm Rodney 35 married to Judy 32 and we have 3 children together. I also have 2 other children with my older sister Maryanne 39 who's a lawyer and has a career first in her lifestyle prospective. But 4 years ago she decided she wanted a child and I being the closest male to her in anyway became her choice of father. Judy was pregnant at the time and sex wasn't top on her list of priorities. So I agreed and fucked Maryanne regularly even after she got pregnant. But her plan for a child wasn't what she got, as she had twins. Which has made her very happy, but also caused her to change her idea somewhat. So instead of raising the child alone as was her plan, she moved in with me and Judy. She also took the chance to bed Judy and now regularly shares our bed. Judy still doesn't know I'm the father of Maryanne's twins. Judy prefers to be a stay at home mom and that suits Maryanne as her twins are cared for by Judy along with Judy's and mine.
The twins are very healthy and have no problems due to their parents being brother and sister. Maryanne had her tubes tried after the birth of the twins. ALL NAMES HAVE BEEN CHANGED.