This is the work of novels and Hollywood. I've not met a person who could talk one long night about an affair and put it behind them. There's a lot to discover: How did this happen? What led to the affair? Was the affair intended to end the relationship? Shake it up? The are multiple reasons for an affair, and knowing which one(s) helps in knowing how to resolve it. Trust has to be rebuilt. STDs have to be checked for. And so on.
As for stuffing things: Have you seen people with those huge jaw muscles? Knots in stomachs? Chronic pain? Stress? When we stuff, it has to go somewhere.
I recommend talking about things. Slowly, kindly, curiously, listening carefully. If you get triggered, slow down more, breathe. Say how you're feeling, rather than hammer away at the content of the discussion. E.g., I feel scared now, or betrayed. Offer comfort and empathy, rather than reassurance.