You won't instantly stop loving him or her.
When people comment about infidelity, the most frequent reaction is: "If he/she cheats on me, it's the end of the marriage/relationship, I quit!" Well, you know what? That's what you think, but I only half believe it. It's a theoretical answer to a theoretical situation, but when it really happens, things are totally different.
Allegedly, about 35 percent of couples stay together after discovering an infidelity. Do you think you know better than them? Well, you don't if you've never had the experience of discovering you've been cheated on.
I can tell you what will happen if you discover your partner is cheating: You'll be awfully angry (possibly to the point that you will struggle the urge of assaulting the cheater physically); you will be terribly sad and disappointed; you will ask yourself "What's wrong with me? Why does he/she feel the need to look elsewhere?" And here's the least appealing: you won't help trying to picture in detail your partner having sex with someone else.
I can also tell you what won't happen if you deeply love your partner: you won't instantly stop loving him or her. Depending on what happens next, you might get out of love later, gradually, but not overnight.
So during a long period of time — several days, weeks perhaps — you will have to live with a series of overwhelmingly strong emotions that are sometimes contradictory that will make it impossible for you to think properly, let alone make any meaningful decisions. My point is that you can't theorize on how you will effectively act in such circumstances.
A very dear friend of mine, very balanced and reserved, discovered that after over ten years of a happy marriage, her husband, having his typical midlife crisis, had a sexual fling with a much younger and particularly attractive woman. My friend was obviously devastated and undergoing all the feelings I described above.
She was seriously contemplating a divorce, even though her husband, who had made abject apologies, appeared to be sincerely remorseful and even though she sensed he wasn't really emotionally involved in the affair.
She had cried, she had terrible outbursts of anger, but they had managed to talk the matter in an adult way. Yet, she was still resentful and was giving him the cold shoulder, limiting communication to the necessary minimum. Nonetheless, she couldn't decide what to do.
There were very good reasons to call it quits and there were equally valid reasons to stay and attempt mending the marriage. Her husband had mentioned he was willing to salvage their relationship, but acknowledged that she was the one who had the final say about that.
She explained that the toughest part of it was the "picturing." She had seen how attractive the other woman was and no matter how hard she tried, she couldn't get out of her mind the vision of "that woman" and her husband in their nakedness, having wild intercourse. It was an utterly disgusting, sullying picture and a huge blow to my friend's self-esteem.
She told me, "It made me think he didn't find me attractive anymore, too old, less pretty. It was disgusting and maddening, but the worst is that it was making me horny."
She couldn't believe it when she heard herself aggressively asking her husband, "Why don't you even try to f*ck me? Aren't I good enough anymore for you?" After an awkward moment, her husband realized that she was serious so he subscribed to her implicit demand, and they had sex. It was the turning point that made her decide not to go for divorce.
I had no trouble believing and understanding this story, for I had been in her position before. In my case, though, things had gone quite differently; my ex-wife's infidelity had gone too far, so the marriage was damaged beyond any hope of repair. Then, I divorced. But I can absolutely relate to my friend's apparently paradoxical feelings and actions.
Notwithstanding all the anger, sadness and disappointment, what you want to avoid above all is hopelessness, the feeling that you have lost all control. I found out that the loss of control, the realization that there was nothing left to hope about my marriage, was terribly worse than "all the rest."
My friend still had reasons to hope and she hung on it. Asking and getting sex from her cheating husband was her way to confirm her hope: it rid her of the thought that she wasn't desirable to him anymore, it sort of washed out the disturbing images she was having, and it made both of them figure out that their connection wasn't broken.
It was quite an odd way of a therapy and a bold move from her, but it somewhat worked for her. Years have gone by and they seem to get along quite well, to the point of having another child.
Don't get me wrong, though: that thing she did was just the starting point of a long healing process. There's just one more point I want to emphasize here: If you find out that you've been cheated on, the key to your future happiness is to forgive, and that applies whether or not you choose to stay in the relationship.
There's no valid excuse for the cheater, but that doesn't mean it's an unforgivable fault. At some point you must say to yourself, "I throw away all the bad feelings and I'm looking ahead. I can't undo what has been done."
Whatever your choice is to divorce or to stay together, you don't want to live the rest of your life with resentment and anger. If you do, you will hinder your own chances of healing.