Marriage is not the idea of man. According to the Bible, God is the Author of marriage. It is God who came up with the idea of marriage. After God made Adam in His own image, He gave Adam responsibility to take care of Eden. Adam didn’t come up with the idea of marriage. He didn’t say to God: “It is not good for me to be alone while all these animals have a mate for themselves.” No, Adam didn’t say that. It was God who said: “It is not good for a man to be alone” Genesis 2:18
God didn’t make Eve out of dirt but He took her out of Adam. That means Eve was created with Adam, at the same time Adam was created, but she didn’t come to existence until God brought her out of Adam to fulfill His purpose of not leaving a man by himself. God brought her out of Adam and gave her to Adam so that she will be a “suitable helper” to Adam.