You -- and perhaps your partner, as well -- might flatly know that your marriage is a failed enterprise, despite your good-faith efforts over a sustained period to make it work.
So, you resolve to divorce, but, pursuant to that decision, take note of all the couples you know that seem to be doing just fine in their partnerships. Many of them might even seem routinely blissful.
Is something wrong with you? Why is your marriage unhappy and destined for closure when so many people around you seem to be thriving in their married unions?