If you and your spouse need a break from the relationship, you may choose to live apart while you decide between divorce or reconciliation. While you're separated, the same legal rules apply as when you are married, in terms of ownership of property. For example, money you earn and property you buy are likely to still be considered jointly owned by you and your spouse, depending on your state's rules about property ownership.
If you are hoping to reconcile, it's a good idea to write an informal agreement about some issues that will surely come up in the meantime. For example, you will need to decide whether or not you will continue to share a joint bank account or credit cards and how you'll budget your spending, which of you will stay in the family home, how expenses will be shared, and the like. If you have kids, you'll need to decide how and when each of you will spend time with them. Here's a sample separation agreement that you can use to create your own.