I have a situation where I have a switch at the bottom of the stairs that turns on a set of canned lights on the same circuit. The current wire used is 14/2. I am in the process of finishing the basement and my wife wants me to add a switch at the far end of the hall to shut off or turn off the same lights on the string. My question is will I have to purchase 14/3 wire and rewire everything or can I just add the traveler separately. I didn't by the 3 way switches yet so if there is a tip on how I should tackle this please let me know.
I have attached an image in what I believed was the correct approach. However, the power source is going to the fixture first whereas the power source is going to the switch first. Can I achieve what this picture is showing by adding a 14/3 wire from the one switch to the other? In the picture it shows one light but I have 6.