Originally Posted by Rich

Assuming this isn't bullshit, you're an idiot for telling the truth. If you wanted to continue having a relationship with this girl, you should have gotten rid of the body and acted surprised when she noticed it was missing, as if it ran away when someone opened the door. Yes I'm an asshole, but hey, I've done an incredible amount of stupid things in my day and I remain married, against all odds.

Also, that way she'd at least have a glimmer of hope that the cat is still alive somewhere.