This is rather hard to measure, because I'm not sure where to put the beginning, and where to put the end.
I'd say my breaking point was December 22, 2010, when he crossed way too many lines, plus I found this forum. He "tried" to "fix" things after that, but at that point I was not as gullible as I had been before.
I did not officially tell him I was over and through with the relationship until March 14, 2011, although I had gone "no contact" with him before that. I had known that it was over, Valentine's Day when I saw his car in my parking lot I left home again and knew it was over, but I did not tell him that until 3/14.
So by that count it's 83 days, less than three months.
If you want to count from when I moved into my new apartment (because that's when it got terribly bad, and I became extremely unhappy, and desperate for some sort of an end), then the count would be about six or seven months, from when I moved, to when he crossed the line and I finally decided it was through.
In other ways, I was in limbo for the last three years, trying to figure out what changed, and what I did wrong, and pretending that everything was going to be okay.
In some ways, I may still be in limbo, waiting for him to show up again and try to "apologize" (which is really "Blame StarCat for everything, but tell her I'll take her back anyway because that's the kind of guy I am."), and constantly looking over my shoulder, wondering when he'll appear.
By his cycle he's due to try again in two weeks.
I still have errant emotions, although they're better now, and it takes more to set me off. I had someone at my desk teasing me earlier, wandering off with various of my personal items and claiming I stole them from him - he meant nothing by it, I used to think his antics were funny two years ago (he really is comical how he does it - usually), but today I felt like throwing everything at him and just going home.
So I don't know where to start counting, where to stop counting, and how to define the middle bit.
I took my best shot.