What is the meaning of eternal marriage?

Lasting marriage is a causal view of good and evil in Buddhism on marriage, such as "once a husband and wife are married for a lifetime", "when a lifetime is spent together, a lifetime is spent sleeping on a pillow". This view is not easy to verify, but it just wants to explain that marriage is hard-won and persuade people to cherish it. Fortune-telling also holds this view, such as "husband and wife have been married for generations, and XiShen intends to be rich." However, the actual deduction of fortune-telling can't help people to look up things that will last forever. It is also important to divide the innate and acquired relationships to calculate the marriage only by the eight characters of life. In this sense, the innate predestination is called the eternal marriage, while the one that can be chosen artificially the day after tomorrow is not called the eternal marriage.