Divorce then Remarry?

During our time, many marriages end in divorce. About 50% of all marriages end up in divorce, and then the divorced couples get married later to someone else. But is this right? The Catholic church specifically states that marriage is final. When a couple gets married, they become one flesh. For this reason, when a couple gets divorced they still remain one flesh. Therefore, if a divorced couple gets remarried to someone else, the couples are one flesh with another person so that they can not become one flesh with this new person resulting in the divorced couple to commit adultery every time they make love to the new person.