Matrimonial issues refer to problems or conflicts that may arise in a marriage or domestic partnership. Some common matrimonial issues include infidelity, communication problems, financial disagreements, and compatibility issues. In some cases, matrimonial issues can lead to separation or divorce. Matrimonial investigations are carried out by private detectives or investigation agencies to gather evidence and information related to such issues. This information can be used in court proceedings, or to help couples seek a resolution to their problems through counseling.