We are what we think about. When we stay fixed on one person, thought or situation, we get caught in the grip of self-centered thoughts. The more we give attention to that which is upsetting, the more strength it has to rule our lives.
It is a mistake to expect all of our needs to be met by one person or in one relationship. Honor and be grateful for that which you receive. Don't become bitter and spend all your time focusing on that which the person is not able to provide.