Pain of loss, for example in relationships, mostly teaches our ego to learn and grow. And that can be from any kind of loss (dearh, divorce, betrayal,..)
I am slowly starting to understand that valuable lessons can be found even in most painful losses. I once read about a guy who found a positive valuable lesson in the death of his 4-years old son.
I can imagine, but don’t want to experience it. But still, a valuable lesson.
Anyway, we learn, we grow (sometimes a thicker skin), become more empathic towards our partners, more grateful and humble, …