Maybe marriage exists because the only way you’re really going to grow as a person is to be completely committed to another person. You’re forced to work out your differences and grow. You just have to, no two ways around it. At least, that’s how it used to be.
Love has nothing to do with what you are expecting to get — only what you are expecting to give — which is everything. What you will receive in return varies. But it really has no connection with what you give. You give because you love and cannot help giving.