Because marital fault isn't an issue, both spouses have equal legal footing, regardless of who instigates the proceedings.
Filing first might lend a few practical advantages, however, depending on your concerns.
Married couples living apart may say they are “legally separated,” but South Carolina’s laws don’t provide for a “legal separation.” Instead, if a husband and wife are living separately, either of them may apply for an order of separate maintenance and support.
Like a divorce, an order of separate maintenance and support can provide for one spouse to make support payments to the other, determine child custody and visitation rights, decide who gets to live in the family home, and divide the couple’s property.
Note: This summary is not intended to be an all inclusive discussion of the law of separation agreements in South Carolina, but does include basic and other provisions.
General Summary: South Carolina law encourages the parties to reach an extrajudicial agreement on marital issues, even a plain, unambiguous agreement is nevertheless finally subject to the duty of the Family Court judge to rule upon its fairness.
The husband or wife can file documents asking the court to rule on the issues of child custody and financial support.
However, a final order in this case will deal with separate maintenance and support only.Usually one or both of the spouses will hire a lawyer to help them come to a compromise on most of the custody and support issues.Their agreement will be put into writing and filed with their separation papers, which ask the judge to approve their agreement.A separation agreement approved by the court which unambiguously stipulates that the terms may not be altered, binds the court as well as the parties with the exception of provisions relating to child support.Statutes: SOUTH CAROLINA CODE OF LAWS Title 20 – Domestic Relations CHAPTER 3. However, you can file for an order of separate support and maintenance as soon as you are living apart from each other.