When having this conversation with someone, you should be as courteous as possible. First, you need to say “thank you.” It takes a great deal of courage for someone to lay themselves bare. If you acknowledge their courage, it might help soften the blow. Next, you should explain your emotions. You shouldn’t make excuses or act defensively, but you should make it clear why you don’t reciprocate this person’s feelings. Finally, you need to look forward and explore your options. Maybe there’s someone else that has your eye, or maybe you’d benefit from being single. The choice is yours, but keep moving forward.
In an established relationship: The sense of calm, peace and stability one feels with a long-term partner can quite often transfer to boredom and apathy for the other. If you’re the bored party, don’t drag it out! Gently tell your partner that you feel a disconnection. Ask them if they feel the same. Regardless of what the answer is, a decision needs to be made on how willing you both are to commit. If it becomes apparent that the flame is extinguished, you should move on. In situations like these, relationship therapy has worked for some couples. It can help assist in understanding the root of the problem. This can help you end your relationship amicably, or help you find a route to a solution that keeps you together.