When I found out my ex-husband was cheating on me with my cousin, I took both his cats and drowned them both in the upstairs bathtub. Then I dried both of them off, double-checked if they had any sort of life in them. Once I was sure, I wrapped both in a towel, put them in my car, and drove to the nearest park. I just tossed both in the stream, and drove back home to start on his goddamned closet, filled to the brim with expensive crap because he's one metrosexual faggot. I put all the clothes in garbage bags, then dropped them off at Goodwill.
I admitted to the hashing of the clothes, but never admitted to killing his cats. He never once accused me of it (thinking I could never be capable of that sort of thing because I'm a huge pushover in nature), and accepted that they just ran off, being both outside cats. Still, though... it's the only thing I now feel horrible about, especially remembering the terrifying sounds they made when they realised they were dying.