In about 6 weeks Apple will be announcing the new iPhone which will remove the headphone jack. Instead to listen to music, you will either have to connect via bluetooth or plug your headphones in using the lightning connector.
Above is a potential third party lightning DAC adapter. Personally I think the photo is a dodgy fake. However, it does depict what an adapter might look like. So all you have to do is connect your current wired headphones into the adapter and the other end in the lightning connector. I would imagine we will see sleeker options to the one shown and versions which include mic and button controls as well. In fact, it would make sense to include the DAC within the button control mechanism, thereby hiding the DAC that is needed when using the lightning connector method.
One thing is for sure. If Apple drop the 3.5mm headphone jack off the next iPhone, everyone else will follow and sales of bluetooth headphones will explode.