It's within the capability of science to one day develop an anti-love potion. Want to fall out of love with someone? Drink the potion, or wear the headset.
Actually, I have semi-jokingly suggested that friends in unrequited love take a certain class of antidepressant for a while, since this is one of the side effects -- it has a pretty good chance of working. So it may be easier to accept, although this is just n=1. (On the other hand, nobody has actually taken this advice..)