Unhappy endings

We don't start a relationship with a true ending in mind. The goal is for it to be good enough not to end. But 18 years in, I am wishing for a peaceful resolution to a marriage that was sometimes great and other times emotionally exhausting. I'm looking for something in the break up that I am pretty sure we never attained in the relationship: unity in purpose? Comfort? A sense of coming full-circle? I want him to be okay. But maybe we are here because I prioritized his emotions over mine. Because I didn't ask assertively enough for what I needed, and he didn't listen even when I did.