The best relationship advice I have seen are these channeled words of God as transcribed and published by Neale Donald Walsch in his book Conversations with God, An Uncommon Dialogue, Book One: “The purpose of a relationship is not to have another who might complete you, but to have another with whom you might share your completeness.” As you say, becoming complete requires the hard, inner work. Some people talk about shadow work. One can also do 12 step work, which I think should be practiced by everyone, not just those dealing with a substance or process addiction. https://medium.com/know-thyself-heal-thyself/spirituality-redefined-ff45cb53eaf2, subtitled "Plus a program for living a spiritual life."