A marriage is no longer a marriage if the two were never one.
Marriage is no longer a marriage when at least one of three things occurs: Your spouse and you are not one, death of a spouse, or your spouse chose to leave you.
Marriage is a covenant agreement between a man and a woman and is not to be entered into lightly. The first marriage was in the Garden of Eden and arranged by God the creator. One man named Adam and a lady named Eve. The two became one in the eyes of God. This was a marriage and no man has the right intervened in what has been done in Holy matron. From that first union man and woman were to populate the whole world.
Since that first marriage man has done a lot to revise the whole plan that God designed. Because of their evil hearts He allowed a man put away his wife with a divorce. This was never God's plan for man. The divorce opened the door to further evil schemes for man to use when he wanted to put away his wife. The list of ending a marriage today is very long and not very well thought out. What changed?
Where did we go so wrong are we no longer considering those laws of the maker? When you got married you become one; you were bound together once consummation took place. The two would love each other and respect each other, just as one would respect himself/herself. But when man decided to make his own rules and engage in affairs, satisfy themselves with concubines and other sorted affairs. Man then was the in control of his own destiny-what a big mistake. Never the less God still loved man despite man being sinful and disobedient. Marriage is no longer a marriage when one mate violates the rules. I don't mean a few in errant rules but that certainly might be the beginning. The marriage is no longer a marriage when one of the following takes place: The marriage was never considered to be one.
A marriage is no longer binding in the eyes of God when one spouse dies. This was Gods original way of a marriage ending. Once a spouse is deceased the widow/widower is permitted to marry again. This marriage has God's blessings.
Finally, a Christian marriage is longer binding if the unsaved spouse leaves the marriage is then considered over and is no longer binding. But it is wrong for the saved person to walk out of the marriage.
God being a loving and forgiving God does not accept abuse of any kind in a relationship. You are to treat each other as you treat yourself.