I think it's Pisces, because Pisces is very eager for love and has great illusions about people or things around him. Once they find that their boyfriends can't satisfy their fantasies, they may pursue what they want and cheat more easily. After all, fish's memory is only seven seconds, and Pisces will not be too attentive to a person.
Secondly, because Pisces has a simple personality, people often cheat her because of her silly personality. Maybe Pisces doesn't understand what cheating is, and if they don't have a strong concept of the word, they will be deceived by men other than their boyfriends. I think Pisces' stupid personality belongs to the kind of person who is sold by others and gives back the money.
The problem of cheating can't be generalized, it depends on individuals. Some people are single-minded about love, while others are new to love, which may be related to their own careers. The bigger their career is, the greater the possibility of cheating. Because people with good careers have more entertainment outside, it is inevitable that they will see things in the world of flowers and flowers, and some gold diggers will attack these successful men. It's hard to say who is the easiest to cheat in the constellation.