Sorry to here about that. You can look on the bright side, you lost your crop but you didn't loose the experience you gained by doing it. The easiest thing for people to say is dump her, but I know how hard it can be when your in a realtion ship. Easy to say but near impossible to do. I wouldn't grow again at your place as it will obviously happen again.
Is the reason she killed your plants because she was worried about getting busted. That is the only logical explaination I can see for this too happen. If that is the case I can see her point as she too lives in the house, but killing them, well, that was going a little too far. Anyways, good luck and rmember: you still have what you learned and she can't take that away from you. Use your knowledge somewhere else or at a later date. Good luck!
TGT