This is an interesting thing to answer. When I see my spouse dating someone else, I will try to follow where they are going and what they will do. Then I will try to meet my partner, and try to talk. I will be honest that I see him dating someone else. I will ask for a decision from him, is still willing to maintain a relationship with me or choose an affair. I am ready with all the consequences. Even if he still wants to establish a relationship with me, not necessarily I want to deal with him again.