This post may seem blunt but it is actually realistic.
If you divorce the best advice I can offer you is to treat it as a business negotiation. If you can start out by receiving $500,000 from the wayward spouse that involves your home and surrounding property then do so.
Please note that you may spend or liquidate much more than this dollar amount when divorcing and assets and liabilities are divided depending on your specific situation.
You need to see an attorney to protect yourself and your interests. You should do this promptly.
Please focus on the betrayal and infidelity of your wayward wife. To reconcile your wayward wife will have to address the part of herself that allowed her to have an affair. This will take a lot of work on her part. She will have to eliminate cheating and wayward behavior from ever being an option for her again.
She has been honest with you about the betrayal. You do not have to endure trickle truth. She told you what has transpired, frequency, and for how long. This is much more than many posters ever get in terms of "knowing the truth."
These are two elements of reconciliation that are normally espoused when trying to reconcile with your spouse after an affair. In my opinion she is doing some type of research or reading about affair recovery.
The paths of reconciliation or divorce may run parallel for sometime.
You may wish to look at it as
Recovery > Reconciliation > Rebuilt or new marriage if her and your reconciliation efforts are successful
Recovery > Reconciliation > Divorce if her and your reconciliation efforts are unsuccessful
I recognize this is simplistic but my point is to show you the paths run parallel for sometime.
You should focus on the betrayal and actions of your wayward wife not on the past number of sex acts or exclusivity. Your focus should be on the here and now with an eye toward the future.
Regarding divorce if you are 45 to 65 years of age or older it is likely you have had a lot of sexual experience.
I do not know what the younger members think we do when the children are out of the house but it is not watch TV. Among single ladies I may wish to date when my divorce is finalized I will find honesty and integrity. I will not find anyone that is inexperienced sexually. The number that is mentioned as a lot is extremely low. A man or woman my age very likely has engaged in thousands of sex acts.
Therefore, do not let exclusivity drive you to divorce.
I will state that normal does not exist in this regard.
I will let the younger members do the math. If you want the numbers, I can provide them.
Reconciliation takes time as does divorce. Protect yourself, recover, give yourself time to heal.
You know yourself, your wayward wife, and the specifics of your individual situation. The decision to attempt reconciliation or divorce is yours.