I am not convinced that it’s a linear process.
First you need to feel that your partner is truly remorseful, owns the infidelity and understands the consequences it has.
And puts in the work to change.
Then there’s a chance for you to begin the evaluation process.
Yo put it simply: if you decide to stay you are precluding yourself a life with someone else who can be honest, true and trustworthy, someone capable of receiving and giving love, to stay with someone who inflicted you a horrible abuse and trauma.
The sure thing is that your current relationship is dead.
You choose to stay why?
You can’t resurrect something that is dead. That’s a fantasy.
You could potentially build something else, something new.
But that depends on a true change of your partner into a safe person and it carries the awareness that the only sure thing about them is this: they are perfectly capable of infidelity.
The time necessary depends on how much they are really changing and able to become safe and make you feel safe.
History doesn’t always have to repeat, but is a pattern indicator.
So acknowledging that they are really putting in the work, that is giving you an eta estimate: what for do you stay? How much they can be present for you and provide you with reasonable proof of being now trustworthy.
From that you might assume a rough estimate, but it truly depends on how deep your wounds are and how much you want it, you want them (still).
You might find out years later that their very presence is just keeping you living in the echo of infidelity. All can come down at any moment.
Are you strong enough and are they worth this Calvary for you in the first place?
If yes, where do you stand right now emotionally?
This is not to discourage you, just remember to be fully honest about what you feel, for you and your wayward.