Altar Sheds Tears
The Talmud in Masechet Sanhedrin, makes the statement that the מזבח, the altar, sheds tears, when a couple gets separated by divorce.
This is based on the dialogue between Avishag the Shunamite, and King David. We are told that David was always chilled, in his old age, and needed someone to keep him warm. This task was given to the beautiful Avishag.
The reason for David’s need of a “warmer upper,” was a punishment for his disrespecting King Shaul. He cut off a section of the king’s garment to show that he was loyal to the king, and could have killed him. Nevertheless, it was not a proper thing to do to the king of Israel. This was why, his garments did not keep him warm, in his old age.
Avishag was not satisfied with her secondary role, of keeping the king warm. She wanted David to marry her, so that she would have equal status with his other wives.
David told Avishag that he was unable to marry her, because the Torah allows a king a maximum of eighteen wives. She would be number nineteen, which was forbidden. She told David that if he divorced one of his wives, a slot would be available for her.
This is where David explained to her that divorce is a very tragic situation. Only when there was no alternative, was divorce permitted. Since he was happy with his eighteen wives, he could not divorce any of them. For the Mizbeach sheds tears when there is a divorce.