The relationship we have with ourselves is about self love. It encompasses awareness of our strengths and weaknesses, acceptance of our past and present, and encouragement of being better today than we were yesterday. When we fail to nurture a friendship with ourselves, we normalize that love needs to come from others rather than from within us. Simple as it may sound, many relationship problems arise from this. Here are some examples.
When we do something special/thoughtful/nice for our partner and expect the same treatment because we assume that our action should signal to our partner the importance of this act for us. When our partner fails to decipher this message, we feel hurt and unloved. In doing this, we send ourselves the message that feeling loved is dependent on our partner's behaviors.
When we blame ourselves for conflicts in the relationship, or we disregard our feelings/needs in order to compromise or keep the peace. In doing this, we send ourselves the message that our needs are secondhand in the relationship.
These situations are familiar to many of us. It is a fault we own, but simply means we are human and capable of growth.
Self love actually enhances our relationships because it gives us greater capacity to love and be loved. It allows us to feel lovable and valuable in the face of rejection, hurt, conflict, or criticism from our partner. And it's self love that allow us to feel lovable and valuable even when we feel all alone in the world. Love with others start and grow within us first. If we do not have self love, we will constantly seek someone who "makes" us feel loved in all the ways we believe we deserve to be loved. And sadly, there is not "one" person out there who will make us feel completely loved. Not because people are bad or incapable, but because it's unrealistic to expect someone to love us more than we love ourselves. Your spouse/partner will love you in the capacity that they can, and your feelings of love will be a combination of how much you feel he/she loves you and how much you love yourself. We must choose to love and this choice allows love to permeate our life.