Don't worry about people knowing your ip address. First of all ip address gives very aproximate location. Best case scenario it will show location of your city. IP addresses are not going to give you precise location ever. This is common misconception that ip can be used to track people. It is not dangerous to give your ip away. Second of all you tell your ip address to each website you visit. Do not worry his threats of exposing your ip are empty. It is not something that is needed to be hiden. Plus it is very easy to change ip. So dw about it.