Question

As far as cheating goes, that's up to your interpretation. Most people in relationships don't feel that way, but it could be a good reason to quit if you do feel that way. I'm not sure you need to tell her, especially if you're gonna quit.

Love is not possession, love is appreciation, you don’t own her and she is allowed to make decisions in relation to her life and wellbeing (not trying to be rude or belittling, I had to learn this same shit myself)

I had to do this a while ago, just tell the truth, answer any of her questions, don’t be defensive, LET HER PROCESS, give her time to think and work towards being better, progress isn’t linear so don’t forget to also give yourself grace, you can do this, love and blessings bro