I think the vast majority of people should not have been married when they got married and to the person they were married to. Some try to tough it out and grind it till the last minute. The smart ones see the writing on the wall and call it a day.
If you are still dragging, here are some signs to help you know that it is over.
If you end up in Starbucks early in the am on Saturday sitting together, but looking at your phones or completely silent.
If you look like hobo and she looks like a million bucks, you already in the retirement phase and she is back in the marketing phase.