But it starts with a relationship between a man and a woman, no matter what the overall implications. And I disagree with your contention that those who are long-term single are so because of selfishness. Every situation is different.
I never used the word selfishness nor have I insinuated it. My position is simple and clear. Man is meant for woman and woman for man. They are inextricably linked. The nature of relationships is virtually infinite but the foundation for relationships is born in the nature of humanity. There is no natural state of permanent onogamy. There is not even an adequate word for such a condition.