Helping spouse during separation time

My former spouse and I obtained a simple divorce in April of 2016. We separated in April of 2014. This was an amicable arrangement. We had no children together and no property.

During the separation we were friendly and she was trying to get on her feet with a bad credit history. I allowed her to put her name on my lease for an apartment in December of 2015 so that she could build some credit history. We never stayed there together, and never resumed the marital relationship, but her name was on the lease for a period of a couple of months. We used the 2014 date as separation in NC.

Was this an invalid separation date? If so, what should I do?
This has been weighing on me.
Thank you for any help you can provide