You’ve probably heard some version of this by now.
Maybe from a therapist. Maybe from a well-meaning friend who has been through something similar. Maybe from a book — and there are a lot of books — that frames the affair as a symptom of a relationship that both of you allowed to deteriorate.
It takes two to make a marriage. It takes two to break one.
And you, still in the acute phase, still unable to eat, still replaying the moment of discovery like a film on a loop — you absorb that idea and let it burrow in. Because part of you desperately wants it to be true. Because if it’s partly your fault, then you have agency. Then there is something you could do differently. Then the future becomes something you can control.
I understand why the myth is seductive. I lived inside it for a long time.
But it is still a myth. And it is hurting you.
Where This Idea Comes From
The shared responsibility framework has legitimate roots in systemic family therapy and couples counseling theory. The idea is that relationships are systems — that both people’s patterns, histories, and behaviors shape the relational dynamic — and that no dysfunction lives entirely in one partner.
For many relationship issues, this is accurate and useful. Communication breakdowns, emotional distance, sexual dissatisfaction, the gradual erosion of intimacy — these are genuinely bidirectional. Both people contribute.
But somewhere along the way, this principle got expanded to cover infidelity. And that expansion is where it breaks down.
Because infidelity is not a relational dynamic. It is a unilateral decision, made by one person, repeatedly, over an extended period of time.
The Kernel of Truth — And the Massive Distortion
Here is the kernel of truth in the shared responsibility idea: yes, marriages have dynamics. Yes, disconnection is real. Yes, unmet needs exist on both sides, and yes, both partners typically have some role in the distance that develops over time.
That is true. And it is completely irrelevant to what he chose to do about it.
Because at the moment where marital struggle ends and infidelity begins, there is a decision point. And at that decision point, there were options. He had them. He saw them. He chose among them.
He chose the one that required your ignorance and your involuntary participation.
Your role in the marital dynamic does not extend to that decision. It cannot. You were not in the room where those choices were made. You were not given the information you would have needed to make your own choices about your own life. You were deceived.
The responsibility for deception belongs entirely to the person who chose to deceive.
You may have contributed to the distance in the marriage. You did not contribute to the decision to lie about it.
What Responsibility Actually Means
There’s a distinction that gets collapsed in the shared responsibility narrative, and it matters enormously.
Responsibility for the marital climate is bidirectional. Two people are in a marriage, and both people contribute to whether it thrives or struggles.
Responsibility for infidelity is singular. One person decided to have an affair. One person decided to pursue and maintain the lie. One person decided that their needs and desires were worth more than your right to know the truth about your own life.
These are not the same category of responsibility. Conflating them is not nuance. It is confusion — and it is confusion that happens to benefit the person who chose to deceive.
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When you absorb partial responsibility for his choices, you carry something you were never meant to carry.
And carrying it is expensive. It diverts your energy from recovery to self-examination. It keeps the focus on what you did or didn’t do, rather than on what was done to you. It activates shame — which is one of the most potent inhibitors of healing — because shame is what we feel about our own behavior, and if his behavior is partly your responsibility, then it becomes something to feel ashamed of.
It also, critically, keeps you in a position of uncertainty about your own value. Because if the affair was partly a verdict on your inadequacy, then you’re still waiting to find out what the verdict says about you. And you can’t heal while you’re still waiting for the verdict.
A Different Starting Point
This is not about making him a villain and you a saint. People are complicated. Marriages are complicated.
But the starting point for your healing has to be accurate. And the accurate starting point is this: he made a choice. It was not caused by you. It was not prevented by anything you could have done differently. And the pain you’re in right now is the direct result of that choice — not a co-production you should be sharing credit for.
Start from that truth. Build from that ground.
Everything else gets clearer from there.
— Sarah
