You just have to understand cryptography to understand why that is not the case, and sending bitcoins does not compromise your bitcoins. See my post above, but I will try to explain it again:

The wallet contains two things, an address (a public key) and a private key. When people send you bitcoins, they send them to the public address. When you want to send bitcoins, you do not give anybody your private key, you use they key to sign a message saying X bitcoins are moving from this address to another address. Again, you do not give out your private key, only the public key. Nobody can sign the message unless they have the private key, but anybody can check that the message was signed correctly and that you control the key for that address.

Maybe reading more about cryptography, like starting here http://en.wikipedia.org/wiki/Public_key_cryptography might help.