I am disgusted by such behavior. The only thing I can offer as perhaps a sort of condolence is...well, now you can begin all over again and that in and of itself could possibly be an enjoyable experience. I know with myself, if something of the sort occurs, at first I am heartbroken, and then when I realise all the new possibilities that have a potential to unfurl before me, I become excited. Somewhat of an example: I have lost/had my purse stolen on several occasions. At first it is a tremendously stressful and unhappy situation for me. After a while, when it really hits me that I have to accept the fact of it all, I start to make a list of what I will need to *replenish* of my stolen/lost goods... ... ...then I get excited because, well, f*** it, it's like starting new all over again.
As far as your significant other goes...try to dump her before it gets any worse. That is beyond disrespectful, especially because it had a ton of meaning for you, and for her to destroy everything like that...ugh...get rid of her as fast and as painlessly as possible!