Men need to start planning prior to a pending divorce. It is better to be prepared by doing some of these things:

Important Papers.
If you have important documents, paperwork, and other records move them to a friend's place or your lawyer's office. It is not uncommon for your spouse to sneak and search your shoulder bag, desk, suitcase, car, phone records, bills, and laptop or pc/mac, searching for financial data and other proof to use against you later.

Stock Brokerage and Bank Accounts.
If you have a joint bank account together visit that bank and split the joint account into two equal amounts and open a new account in your name using that half. If you make the most money do not leave your kids and their mother without any money to live on. This will only exacerbate the situation and you'll end up paying anyway. Continue to have the debts paid and then inform your current spouse of what has occurred. The same goes for any joint brokerage accounts. While it is true there may be tax consequences it has to be done.

Joint Loan & Credit Cards.
Close all joint credit and loan accounts by disclosing to the financial institutions, charge cards by certified mail with a return receipt that you are no longer liable for the charges and fees from your current spouse. It may be possible to open a new account. Inform your current spouse so she is not embarrassed at the gas station when the credit card does not work.

Living Expenses.
Two people, with one being your child, are generally unable to live on less than one, and even more so if they are living apart and attempting to support two households. Therefore, when living separately, it is an optimal time to trim your expenses as much as you can. Close any unnecessary monthly bills such as extra cell phone numbers, land-line telephones, premium cable tv packages. However, do not cut off the utilities on your children and your spouse without giving them ample notification. Make sure you can back this up later because leaving your spouse and children without electricity or heat in the winter time does not make you appear with the family law court judge.

Get a Divorce Lawyer
Find a good experienced family law attorney by arranging a consultation as soon as possible. Do not become worried, there are some attorneys who offer FREE initial consultations. In the very first discussion, you will leave their offices with a solid strategy and some good advice for your individual situation in regards to your spouse, children, work, custody rights, visitation, costs, timelines and more. Among the divorce advice you'll receive is that you'll be advised to not sign any documents prior to them reviewing it. There may be other matters to discuss as well depending on your situation.