Hi H.,
I've had this very same problem with my son, and we were, at the time, actually seeing a psychologist for some help with aggressive behavior due to Blake's inability to express himself verbally (this not being related, however I felt I needed to tell you why we were seeing the Dr. so you would understand that it was related to his verbal skills and that he was not a problem child).
Anyway, my son, Blake, knew the rules when Mommy was home and was use to the routine. Whenever Daddy was home and the routine changed, he would have "the MELTDOWN". UUGh! It was awful. He would do what I asked, but if my husband asked something he didn't want to do, he would freak out.
What the Dr. told us was that I needed to affirm my husband in my son's eyes, even if I didn't feel as though the suggestion was a mountain (not a mole hill). This was very difficult for me as when my husband is home our routine goes out the window. I made sure that my husband understood our routine, if there were going to be changes I could foresee, I would prepare Blake for the change ahead of time. For example, Daddy is home and we are going to do "the change" instead of "the routine item" to spend special time with Daddy. Eventually, this did all pay off.
Children are very manipulative, and sometimes we don't even notice. If Blake thought he could play one of us off the other, he did. Usually it would resort in a disagreement between my husband and I. That is not to say that we don't still disagree, it is just to say that I support him in front of my children, and we discuss it later behind closed doors. The exception would be if he truly is in the wrong, then you need to make diplomatic suggestions (LOL). I hope you find this helpful.
Thanks for hearing me out.
A.