Anyone who has been in this position, I would be so grateful for any advice you have.
I've never cheated, though I have been cheated on.
I have however overcome addition, drugs in my case.
What worked? Fucking hard work.
Therapy, facing consequences, accepting I was being totally destructive and selfish, being realistic about the likely outcome of me continuing such toxic behaviour, mindfulness, filling my life with other things, picturing the better future I want and starting then sticking to medication for an underlying cause (bipolar) of my addictive tendencies.
And then constant vigilance and staying focused on staying well.
I'd imagine the same sort of process would work for a behavioural addiction like cheating.
You know it can't end well. Every message (just like for others every drink / every hit / every line) is prolonging the path to recovery.
It's hard work but it's always worth it to be free of an addiction.