If you and your husband or wife are separated or about to be separated, you may feel like you're divorced, but you are actually very married. This means that you may be emotionally split from your spouse, and perhaps living in two separate locations, but your money is still likely very much intertwined.
As Geoff Williams writes, your money situation is about to change. You know your life is changing, but you may be tempted to keep as much of it as unchanged as possible, especially if you have children. But the sad fact is, you're going to have to make financial sacrifices somewhere - you now have two households that need to be supported with the same pot of money. If you can get into that mindset right away, that you and your soon-to-be ex will both be living on less, it may help you avoid having your spirit completely crushed later.