Legal separation actually doesn't exist in the State of New Jersey. Many people just don't know that. They read about it on the internet or they hear about it from family members or friends, and it's a concept that does exist in some other states, but not here. What you need to know is that you can physically separate from your spouse, but it's not going to be recognised by the court. You can go to a lawyer or you can set up temporary terms of separation with your spouse, but it's not going to be an enforceable contract per se.
You can work with your spouse and say, "We're going to have this trial separation for a period of time, maybe six months. I'm going to live here, you're going to get an apartment and we're going to split the bills in this particular way. We're going to take care of the kids in this particular way. We're going to set up a type of visitation schedule," or otherwise, have some type of support arrangement and then see if you want to take the next step to a divorce, or ultimately reconcile your marriage. Many people do that and they are faithful to the ultimate terms of their separation if you will. But it's not actually a legal separation that is formalized in any particular manner.