Some of the biggest challenges in relationships come from the fact that most people enter a relationship in order to get something: they're trying to find someone who's going to make them feel good. In reality, the only way a relationship will last is if you see your relationship as a place that you go to give, and not a place that you go to take.
Tony Robbins (2007). “Awaken the Giant Within: How to Take Immediate Control of Your Mental, Emotional, Physical and Financial”, p.451, Simon and Schuster