Take this for what it's worth... as there's no SCIENTIFIC research that says EVERY person that has these Zodiac signs is a cheater, but here we go... take a deep breath...
According to data from Ashley Madison (again, take it for what it's worth,) Capricorns are the most likely zodiac sign to cheat. And, it seems that Capricorns make up the majority of Ashley Madison users.
According to the site, here are the Top 5 Cheating Signs:
Source: Pop Sugar