When expecting to receive ether from someone, is the ether lost if i provided a wrong address? Or can the transaction then not compute?
The Ether would only be lost if the wrong address provided is also a valid address which would allow the transaction to confirm.
Please note that a valid address does not require that the address was generated from a private key. It only means that the address matches the format required for a valid address.
Ether cannot be lost if it is sent to an invalid address. Ether sent to an invalid address will not result in blockchain confirmation.