get a phone that has a light that lights up when an extention in you home has been picked up. if your being tapped this light will go on when you make a call.
I had just such a phone and I was able to see whenever someone was listening in. I had a neighbor who was an engineer specializing in telephone communications. He said, in fact, someone was listening in.
Recommendations
1. Whoever you are dating, break up with them.
2. Start dating a federal judge. The marshalls are very good at dealing with stuff like this.
3. If you have phone sex with any of your friends, stop. After a while the listeners will get bored.