Most people believe that partners who cheat plan to find someone else, but it is often a surprise invitation at the right time when this pattern begins. They are going through their daily life when a person they do not know suddenly offers them an opportunity, and they are often unprepared for it. A person who might never have thought of cheating on their partner will suddenly realize they can do it without consequence, and they might just take the bait. This can be a recurring pattern once they learn how it works.
Being desirable by many is something most people are not used to, so a person making a sudden proposition can be very attractive. It feeds the emotional needs of the person who is propositioned, and they might find it exciting. They might begin to look for potential partners in their usual haunts, or they might go to new places to see what they can find. It becomes a habit after only a few encounters.
Getting caught is the biggest issue for this type of person, and they seldom believe it will occur. They have little or no connection to the people they are with outside the relationship, and they think this fact will keep them safe. They fail to see their desire for their partner waning, but that is often what tips them off. It will often come as a shock when they are caught, and many of them confess because they have not planned on how to react when faced with the truth about their behavior.
There are few people going into a relationship planning to cheat on their partner, and that is part of what makes it even more difficult to face. The person who takes advantage of opportunities is thinking only about how good it feels to them at the time, and they have little thought for the future.