In one sense, those who have had multiple marriages and divorces are no different than those who have committed many other types of sins. They must confess all known sin and seek at the moment of their salvation to walk in a manner that is worthy of the Lord. The consequences of marital infidelity though, are often enormous (especially if children are involved). One may need to financially support several sets of families, or work toward mending all kinds of broken relationships, including blended family concerns.
To answer the question specifically, it is sometimes impossible to “unscramble the egg,” given all of the intertwined relationships. The general answer from Scripture is this: Paul admonishes us to stay in the state we were in when we were called to salvation (see 1 Corinthians 7:20, 24). In that chapter, Paul teaches that one is to stay in the state they were in when Christ called them to Himself. So whether you are single, having never married (Paul calls this state a “virgin”—vv. 25-27), married, divorced (Paul calls these the “unmarried”—vv. 8-9), or widowed, stay in that state.
In other words, whether you are presently married or unmarried, endeavor to serve God in that state with all your heart. If you are single—however it has occurred—heed Paul’s own lifestyle of singleness to optimally glorify God. This way you will be able to serve Christ in an unhindered fashion (cf. 1 Corinthians 7:8-9, 28-35).
Some may assume, given the above paragraph, that having been previously divorced, they are forbidden to remarry. Such a prohibition, however, does not appear to be the case. Paul tells the previously married and widows, “It is good for them if they remain, even as I. But if they do not have self-control, let them marry; for it is better to marry than to burn with passion” (1 Corinthians 7:8-9).
Paul goes on to say, “Are you bound to a wife? Do not seek to be released. Are you released from a wife? Do not seek a wife. But if you marry, you have not sinned; and if a virgin marries, she has not sinned. Yet, such will have trouble in this life, and I am trying to spare you” ( 1 Corinthians 7:27-28). Paul himself says that it is better if they remain single; however, he acknowledges this is not a command, but a concession (see vv. 6, 28, 32-35, 39-40). If they should choose to marry, they must marry “only in the Lord” (1 Corinthians 7:39).
Because Paul allows for remarriage, one must not assume that they can confess Christ and divorce their believing spouse in order to marry another. Paul gives a strong prohibition to those who are in Christ and who are presently married: they must not divorce. “But to the married, I give instructions, not I, but the Lord, that the wife should not leave [divorce] her husband (but if she does leave, she must remain unmarried, or else be reconciled to her husband), and that the husband should not divorce his wife” (1 Corinthians 7:10-11).
If you should unbiblically divorce in this manner, you have the responsibility to remain unmarried and seek reconciliation to your spouse. The only exception to this, of course, is when your spouse is choosing to live in unrepentant adultery. Remember, remarriage is permitted for the faithful partner when the divorce was on biblical grounds. So those Christians who divorce because of unrepentant sexual sin by their spouse are allowed by God to marry a believer (Matthew 5:32; 19:9).
If you are unsure about the biblical position of your particular situation, you should seek the counsel of your church leadership before you embark on another relationship.
Grace to You