How long do you feel is appropriate to stand by your M? Until she cheats? Until she says it's over? Until the divorce is inked? Or until you have really moved on, grown, the dust has settled, it's a year after your D is FINAL, you can see there is no sign of change in your ex, and you are interested in using your new skills to build with someone else?
I read some where that you should heal for at least one month for every year you have been married.
For me that was 3 years after my divorce. 28 years married.