No one prepared you for your best friend's divorce

I'm 40, so I've seen a few divorces amongst my friends and acquaintances. But my best friend is heading towards divorce. I've known it's been coming. But today she told me her husband is on a waiting list for an apartment nearby, and he's choosing what furniture to take. I broke down in tears.

This man has been in my life for 21 years. They started dating the same year my husband and I did. They're godparents to one of my children. They're both trying to remain civil and have said that none of us need to choose sides or stop being friends with the other person. I just didn't realize I would be affected this much. I cried for a long time today, and I felt like an ass for not being able to support her right at that moment because I was having my own breakdown about it.