Conservative Bible students and scholars come to very different positions on the matter of divorce and remarriage. This naturally makes the matter even tougher, but this is the reality of what we face. On the one hand some believe there is no basis for divorce under any circumstances and to remarry is to live in adultery. On the other hand others believe God allows divorce and remarriage for three circumstances: (1) adultery, (2) desertion of a believing spouse by an unbelieving spouse, and (3) if a person becomes saved after they were divorced, etc. because they are beginning life anew.
Ephesians 5 and 1 Corinthians 7 are key Pauline texts on marriage. From these passages, especially 1 Corinthians 7, it seems evident that Paul’s view is that: (1) a believer whose unbelieving spouse has deserted him is free to divorce and remarry; (2) a believer who was divorced when an unbeliever is free to remarry; and (3) a believer who is the innocent party in a divorce involving adultery is free to remarry.
Having said all this, we should still keep in mind that God hates divorce and that Christians should seek restoration of their marriage, which often takes a great deal of time. This may mean separation until the offending party makes the necessary changes as a protection for the abused party, etc., but sometimes this does not happen and the situation becomes so complicated that divorce may be the only solution. Separation can be done as an act of tough love to get the other partner to come to their senses, but again, each situation needs to be evaluated carefully with the counsel of others in the body of Christ.
My experience with people in this type of situation has shown me that many people do not want reconciliation and are not willing to give God a chance to change their spouse. They are so full of pain and resentment, they simply want out, which is understandable. What is needed is good biblical counsel, time, and a great deal of prayerfully waiting on the Lord.
Other than to point out a few scriptural principles and the different convictions on this issue, I really cannot give adequate advice via email due to the many and complicated issued that are involved in every situation.