mtex,

I can see why you are very upset. I would be very upset too if I felt someone was taking things out of my house, but is there any possibility that on some level she feels she was doing you a favor? Maybe she thought she was "rescueing" that stuff. You said yourself that your ex is not sentimental. Maybe she felt that she was saving it for you and your girls from the time that you were depressed and unable to care for the kids. Maybe she was afraid that he would throw it away and you would be unable to care for it just as you were unable to care for the girls.

Regardless, she shouldn't have made up an excuse about why she did it and she should have told you sooner about it. (Of course, maybe she was trying to get a reaction from you.....) I'm sorry this happened to you.