The Bible strongly sees remarriage after a divorce an act of committing adultery. Jesus also teaches it in the New Testament that no married couple should be separated. This idea is in both the Old and New Testament and people can see how much God does not want marriages after a divorce.
This is because the sacrament of marriage is very holy in His eyes as a marriage of a man and a woman allows them to enjoy sex without committing a sin. God wants married Christians to produce children who live in a Christian household. A divorced man or woman can only get married without committing adultery is when their exes are already dead.