Umm, I am not sure I would worry about it all that much. I grew up in a family that always had two of everything. Every birthday for each of the kids was celebrated twice, once with Dad's side of the family once with Mom's side of the family. Christmas Eve with Dad's side of the family, Christmas Day with Mom's side of the family. Alternate Thanksgivings and New Years, etc, etc. I never thought anything about it. Never thought it was unusual at all. My mom's parents would ask about the well being of my father's parents when we visited, and never said anything negative about them, and vice versa. If something awful would happen (god forbid) one side of the family would stay with the child/children at home, the other would go support whoever was in the hospital. Then they would switch places. To be honest it seemed perfectly normal to me. And if anyone found the arrangement stressful (for example my parents) no one ever showed any signs of it. As long as both families enjoy their time with Cam and do not say anything negative about each other, I think things can go smoothly.