In a perfect world divorce would not exist. But we're not perfect, or in a perfect world. God made us with the freedom to choose whatever path we take, and in the case of marriage two people are needed to be on the same page with each other. Unfortunately it doesn't always work that way. Choices are made that have damaging effects, and when bad choices are continually made, and a path is followed leading away from home, divorce is inevitable.
God is brokenhearted, yes. But that doesn't mean we will be condemned to the pits of hell for bad choices made by ourselves or our ex's. God looks into our heart and sees whether or not we will cling to Him in those situations, or cling to the situations themselves.