My wife made me promise

I'm a rather boring person, I don't do anything exciting and care for my wife and 5 children. My wife Elaine 35 is happy with her life and how we're are doing, but he was unhappy that her sister Kerry 33 was lonely and not doing well at anything in her life. Kerry is her only sibling and had told Elaine she just wanted a great life like hers. Kerry and Elaine could pass for twins. Kerry doesn't have any success with men and recently lost her job, so Elaine had her move in with us. Elaine can't not have any more children and I accepted that. After we had married and started having our family we never took precautions during sex and were happy having 5 children and would've continued having more. But due to problem with our last child's birth she can't have anymore children. So with Kerry living with us and unemployed, Elaine saw it as a chance to give both Kerry and us happiness. First she talked with Kerry and with her agreement, turned to me. Elaine wanted me to get Kerry pregnant and that way we could have another child and give Kerry a family also. I wasn't sure about her request and then with Kerry also asking for my help, I agreed. But I was still unsure, as being pregnant and unmarried still puts a stain on a woman even these days in our community. But Elaine said in the past and even in the bible, men had more than one wife and Kerry will be my second wife. But not married to me in a legal sense, but in a personal commitment between the 3 of us. Kerry started sleeping with us both and she got pregnant and had a daughter in February. Only change in our lives was buying another larger house, out of town away from close neighbors and enlarging it. So I now live with my 2 wives as Elaine refers to her and Kerry and 6 children and everything is going along great. Both Elaine and Kerry are happy and Kerry wants more children.