I've written and thought about this before, but I continue to be amazed at the misuse of the word “love”. When most people use the word “love”, particularly in a romantic context, what they usually mean isn't actually love for the other person at all.
What they actually mean is “I want you. I want you to meet my needs, I want you to complete me, make me whole and happy, and I'm convinced that you will do that. And I'm going to use you in the attempt to do so, without any actual concern or regard for you or your wellbeing, as long as I'm getting my needs met. I will run roughshod over you and your own needs and preferences, if I notice them at all, in an attempt to get you to give me what I want.”
Of course, not all people are like that (at least not to that extreme) or mean that when they say the word “love”. And as we're imperfect human beings, I believe even “true love” can be tainted by that type of selfishness. We're selfish beings by nature, and we're all prone to be more willing to get our own needs met than to seek to meet the needs of others.
But nevertheless, that idea is out there, and there are a lot of people who mean that when they say the word “love”. The irony is that it's such a parody of real love, which is basically the opposite of trying to get your needs met using another person. It's giving of yourself for the good of the other person (NOT in an unhealthy, codependent way, which is another way of using them). It's a committed bent toward understanding the other person and their needs, and attempting to do them good insofar as you are able, even when it's inconvenient, painful, difficult, or you just don't feel like it.
How do we know what real love is? The pattern is Jesus, the God of love who lived among us and showed us what it means to love:
By this we know love, that he laid down his life for us, and we ought to lay down our lives for the brothers. But if anyone has the world's goods and sees his brother in need, yet closes his heart against him, how does God's love abide in him? Little children, let us not love in word or talk but in deed and in truth. (1 John 3:16-18)
Love is patient and kind; love does not envy or boast; it is not arrogant or rude. It does not insist on its own way; it is not irritable or resentful; it does not rejoice at wrongdoing, but rejoices with the truth. Love bears all things, believes all things, hopes all things, endures all things. (1 Corinthians 13:4-7)
If someone tells you they “love” you, but their actions toward you don't demonstrate this type of character, it's not love.
If someone tells you they “love” you, but after years together they decide they don't “love” you anymore, they didn't love you. They mean that they no longer feel like you're meeting their needs and they want to go elsewhere to find someone who will.
Real love persists through difficulty, boredom, and even undesirable behaviour on the part of the other person (note I am NOT talking about putting up with abuse or disrespect, particularly if you're dating someone; get out fast if that's going on, because a real relationship involves real love on both sides). Real love commits to act lovingly because that is the character of God, even when the other person isn't particularly lovable. Real love knows that the only One who can fully meet our needs is Jesus, and goes to him for that filling so that we're able to love those around us even when it's tough and we don't feel like it.