How about validating her feelings about the schedule, asking what she would like in a new schedule and ignoring the part about her family?
Something like "W, I understand that not seeing S for a week upsets you and I appreciate you voicing your feelings. What would be a fair arrangement to you?"
Me: 31, W: 29 T: 4 M: 2 Kids: 3 (SS: 7, SD: 4, D: 3) Separated, still living together: Nov 2013 Separate bedrooms: Feb 2014 W working away; kids with me: Nov 2014