So, I have another question - it seems like I don't understand exactly how bitcoins are stored.
I thought, once a bit coin has been created, it can never be destroyed, because it is stored in a peer-to-peer-like network.
Is that wrong?
You are correct. The blockchain (the peer-to-peer network) stores a public address. If you know the public address (we say bitcoin address) you could look on the blockchain and see your funds. However, to spend those funds you need a private key that is associated with the bitcoin address.