It could simply be that she wanted the object and lacks the ethical reasoning to procure one otherwise.

You may have made a connection to an emotional response that isn't there...of course you may not have.

But bottom line,,,the taking of something that belonged to you is an issue of broken trust. That may be the most important aspect to the incident.

Can you trust her again?...

I don't know but I do know that it probably won't happen until you are all able to sit down and communicate. Understanding why,,,her having true remorse and making amends will be a base for further development of trust.

Jealouscy is not generally focused upon the unrelated to the object...but in disordered minds that object can shift...

IMHO.

Lenny