The question is short and to the point—it sounds like you feel betrayed and are angry, want revenge, and want to know how to get over this. I feel embarrassed that my answer is so much longer than the question, and I ask for patience; this is a painful and difficult experience.
I have questions, too. I wonder how long you have been married, if you have children, and if there have been other instances of betrayal that may not be confined to the sexual area. I wonder about your ability to communicate. I worry that you and your spouse are not partners, but adversaries, and maybe have been for a long time.
Let’s focus on dealing with anger. You say you “get snarky.” Are snarky remarks a way to gradually let off the anger, preventing a full-fledged rage response? Have you been angry for a long time?
It sounds like you want revenge. That’s understandable—an eye for an eye, so to speak. Unfortunately that leads to blindness all around.
A poet, Ron Padgett, advises staying angry for a week, then dropping the anger but not forgetting the reason for it.
Sounds good, but how?
Some ways to release anger are: physical activity, emoting, meditating, writing in a journal, doing art, talking things over with friends as well as the person who made you angry in the first place, seeing a therapist if the anger is of long duration. All these methods work; try them all or the ones you like best. Consulting a couples therapist deserves primary place on this list.
Couples therapy will help you communicate with each other in a protective environment, where you can both be clear about your feelings and what may have caused this painful breach of trust, so you can figure out together what to do next. As you each learn how the other feels and thinks, you may develop more empathic responses to each other, and the marriage will strengthen. Alternatively, it may become clear that the marriage cannot continue—in this case therapy may help you part with less rancor, so that the good memories of your relationship can survive. This is especially important if you have children, but even if you don’t you will part more completely if you’re not bound to each other with rage, which can act like glue and prevent you from moving on with your life. A couples therapist can also help you decide if individual treatment might be helpful.
Most important: remaining angry for long periods of time causes physiological changes, such as a rise in blood pressure and literal aches and pains, and it sets the stress response going on a 24-hour basis. Not good. So it’s a question of health to learn ways to deal with strong emotional responses.
I wish you and your spouse good luck and patience in learning how to communicate with each other and live without fear, anger, or despair.