Fair point, SunnyB. Stbx makes a point of correcting D4 when she calls his place "your house". He says "you mean our house?". But she has to pack pjs and clothing every time she goes there. Whatev.
Interesting to note: stbxmil who still has a key to my home and used it last time she came over does NOT have a key to her son's home. Wonder if his GF does...