Thank-you for sharing.
Firstly, ignore the ***** like Dowie trying to get you to get rid of your dog.
Secondly, these things never happen without a cause - Even if it's something we missed or did not see, there will have been something that happened to trigger this behaviour. Any change can have an impact, from pregnancy to a new perfume, a change in routine or even a change in the time you do something.
Since the dog was in the other room on the first occasion, that reason can't reasonably be ascertained.
The problem with rescue dogs is that they come with a history, usually (but not always) of abuse and neglect, so you're already in a position of never being able to know everything. However, I've had nothing but positive (albeit sometimes exasperating) experiences with rescues over the decades, and the continuation of so many centres is testament that most other people have similar experiences.
The other two incidents may well be possession, as you say - Some dogs do bond to one member of a family more than others. In such a case it's often helpful to go through obedience training again (especially reward based) but with your partner being the one in charge.
Another common cause is an injury or illness, which again may not be apparent, so a checkup at the vet could also help.
Someone has already given up on every rescue dog out there, at least once, so I definitely applaud your determination and wish you the best of luck.