Does she have a court order barring you from the house? If not, why are you asking her permission to enter your own home? She obviously thinks you have a key and said to go ahead, so what's the problem?

Honestly, I feel you're somewhat wrapped up in games with her. You're giving both her and the assistant too much power.

M 16 yrs, WH62, P54
3 adult blended kids
EA 11/13, BD1 6/14
PA fall 14, BD2 2/15
Piecing 2015, BD3 12/15
Separated 4/16
WH moved OW in 5/16
Divorced 6/15/17