Sure but I'd imagine that when you actually start contemplating a breakup you already identified an issue and tried to fix it or work around it. So if you are still entertaining that thought it's because you ran through your options and you're mostly out of them.
You might decide to live with this but again, if you started thinking about it to the point where you consider breakup then it's likely a serious enough issue and it doesn't get better.
This shouldn't stop you from trying to the point where by all definitions the relationship is dead. There's no rule for this other than a rule of thumb. But that one pretty much suggests at that point you are just delaying the inevitable. Unless all you actually need to fix it is time.
You might decide to live with this but again, if you started thinking about it to the point where you consider breakup then it's likely a serious enough issue and it doesn't get better.
This shouldn't stop you from trying to the point where by all definitions the relationship is dead. There's no rule for this other than a rule of thumb. But that one pretty much suggests at that point you are just delaying the inevitable. Unless all you actually need to fix it is time.