My first suggestion to you is to examine why you felt justified to cheat out of revenge for a fight. Is this how you behave in all of your relationships? Is this the kind of girlfriend/mate you want to be? If you truly want a lasting, good relationship, you can't be doing stuff like that. If you have a fight, you deal with it, not get revenge. That is the quickest way to end a relationship, whether or not your partner knows. Why? Because you're not being the best partner you can be to your mate. You are participating in making the relationship unhealthy and toxic.
If you want to move forward and start fresh, first develop some healthy relationship habits for yourself like learning how to cope with fights and anger rather than getting revenge and or cheating. If you don't want to be in the relationship, end it, don't cheat.
As to whether or not you tell him of your cheating, that's up to you. If you believe it will come out later on it's own, it's better he hear it from you, and you would only be delaying the inevitable, creating more hurt in the long run. If it causes the relationship to end, then you must accept that as a consequence of your action. If you really wanted to be in the relationship I don't think you would have risked it all for revenge cheating. Also don't keep him in the relationship under false pretenses. If he wants to leave, that's his choice. Next time make better decisions for yourself and your relationship if you truly want to stay in it.
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