Yeah, sit down with her and find the way back to marital harmony. "For better or worse." You walked the walk & talked the talk. Prove it.
Don't scar your 7 year old with another "dad." He's gonna put his hands on your blood...probably in kindness, but, possibility in discipline. You can stop that probability/possibility now. This is this child's only childhood. Don't compromise it, hate. Don't do it. Let this child have his childhood unen bered sans the catastrophe of divorce.
Your marriage was pure once upon a time. If you thought you were going to go 50 years and have it pure at the end you were mistaken. Divorce now and the next woman you find you'll have problems with, maybe the same, maybe different, but, you'll have problems, dire ones, like you have right now. You gonna divorce then too? Make your fight now, on the sacred ground where you exchanged vows with this woman.
Swallow your pride and take it upon yourself to heal your marriage, to do everything in your power to save it. Don't keep count. Throw the count out. You, not her, you. Look at yourself and take responsibility for your failings here. Don't look at her, hate. Just you.