When any of your contacts go through a divorce, there are a number of steps we recommend you take within your database in order that you don't erroneously send out correspondence addressed to them as a couple or make any other errors of this nature.
First, it's not a bad idea to enter this information in the Important Info section for each of the former spouses, i.e., to indicate in each of their Important Info sections that Contact X was formerly married to Contact Y. It's a quick visual cue on each of the record's Overviews.
The other items you'll want to take care of, particularly if you use Redtail for mail merges, are:
1. Go to the Family Head's record and click Clear Family in their Family section. Each of the contact's will now need to be their own Family Head. If any children are still living with the parents, you will need to decide which parent to link to via the Family section. You can then go that parent's record, click Create Family in their Family section and then add the children as family members. You'll also want to go to the other parent's record and simply click Create Family in their Family section (though you won't be adding any children) — this will establish them as their own Family Head.
2. Link the children to the parent that is not linked via the Family section via Memberships.
3. Link the former spouses via Memberships as well, using an Individual relationship such as Ex-Spouse, Ex-Wife, Ex-Husband, etc.
4. Give each of the former spouses their own Family Name.