Due to their tendency to be unsure of themselves, Geminis are the most prone to cheat on you.
One day they might be with you and the next find someone else with whom they feel more compatible. Make sure you are certain of your relationship and their affection for you while you are with a Gemini.
A Taurus is also more prone to cheat on someone because they are unsure of their own feelings for you. They can't commit to anything or anyone for an extended period of time since their emotions shift quickly.
If they have discovered someone better, they won't hesitate to commit to them even after finding them. Although they might never cheat if they are genuinely and utterly in love, it happens very infrequently.
The most devastating heartbreakers are Scorpios. They will probably cheat on you and could possibly keep you as a potential partner.
Keep your eyes and ears attentive when with a Scorpio and don't disregard any indications of betrayal.