Regardless of the age of your children, if you decide to divorce you'll need to bring this to light at some point. The only time this doesn't come into play is if any of your children are too young to understand what is going on.
Far too many people put off estate planning until it's too late. People may tell themselves any number of excuses for avoiding this critical process, such as that their family is still growing and changing or that they don't have enough assets yet to make the process worthwhile. In reality, if you have anyone dependent on you, either a spouse or children, if you have a retirement account or a home, you really need to create a last will and estate plan. After all, you can always review and update your will.