The worst someone can do to a loving spouse is break there trust. It just means you have created a crack or rather broken that stronger will that has kept both of you together. That thing that can make them sacrifices all for you. You have created a dent that cant be wiped off.

In as much the wrong was done or not. But the individual has been shaken and it wont be easy to return back to factory set.

That is why when a spouse cheat on there partner no matter what you do they will forever think you are same person. They may forgive but they will never forget . Any action you take you will be suspected of doing wrong.
By a singular act you have destroyed trust and
broken that will and strong connection .

But then how do we clear all doubt and make this person be able to trust us again? How do we make amends till what is broken if fixed?

How do we bring back the old flames.
How do we know for sure we have cleared all doubt? How do we fill whole again?

If a spouse has broken your heart before. How did you feel how did you overcome the hurts.
It hurts so much when you feel your world is crumbling yet by one person's singular act. You feel there is no more air to breath, your heart racing the chest is congested and you can hardly breath.
How did you overcome all that?

By starting all over again.
Re-ignite the flame in the relationship by compensating for your wrong deeds, that negative impression that must have been created in your partner's heart towards you, go an extra mile to prove it wrong.
But for some people, broken trust can never be regained!