What is the ruling on continuing a marriage with a wife who uttered the name of a man other than her husband during foreplay and justified it by thinking about something related to that person, knowing that the husband has been unable to overcome the matter and is thinking about another woman with whom he had a relationship before marriage?

Your relationship with your wife should be built on good faith, and what emanated from her may have been a slip of the tongue. So, do not be harsh with her in reproof. You must forget what happened and dispel misgivings from your heart. As for speaking with the woman with whom you previously had an illicit relationship, it is obligatory for you to keep away from that and to repent to Allah, for enticing that woman is considered tak̲h̲bīb, which is prohibited.