One of the most notable commentaries by Dr. Spiros Zodhiates on First Corinthians is chapter seven. The issue of divorce and remarriage is hinged on the decisions that can be made only by the individual marital partner. Because of sin, life is very complex that frequently there are no simplistic answers to those complex questions.
It is unclear what prompted Paul to write on this subject, but what is clear is that Paul felt the need to address the subject candidly and seriously. Marriage is a God-ordained union that Paul whole-heartedly espoused. When there are issues in the marriage the primary goal is restoration. Other issues such as fornication and adultery are dealt with at length by the apostle Paul.