Unfortunately, what can be the most difficult issue in a divorce is the issue of child custody. By and large that should not be the case. Both you and your soon to be ex, should focus on what is best for your child(ren). This isn't about you! Still, things sometimes go wrong and you need to have a realistic take on your options.
There are basically two aspects to custody in New Jersey.
One is Legal Custody. Legal Custody amounts to who has the right to make significant decisions in your child's life. Those include educational decisions and non-emergent medical decisions.
The other aspect is Residential Custody or Parent of Primary Residence. Your child has to live somewhere. Usually your child will live mainly with one parent or another. In some cases, there will be a Joint Physical or Residential Custody arrangement. That is an arrangement where the child splits his or her time evenly between both parents' residence. In the past, this was only done if both parents agreed to it. It was not something a court was likely to order. There has clearly been a shift here and some judges are open to it, in some circumstances even if one party opposes it. Realistically, parties should not propose this unless they live reasonably close to each post-divorce and know that each is capable of being an effective custodial parent. Anyone who proposes doing this because they think they can save on child support or because they believe they have a "right" to it should give serious consideration to an important question, are you putting your child first or are you putting money or your ego first?
Now some people start out taking the position that they should have Sole Legal Custody of the children. In other words, the child should live primarily, maybe exclusively with them and Legal Custody should also be exclusively theirs. At times that is the right position. If your spouse is abusive to the children, it's clearly the right position! If your spouse is an alcoholic who you know is likely to be drunk around the children and to drive drunk with them, it's the position you want to take. In other words, you have a spouse who, even if they are a "nice" person, isn't fit to be a parent. This is not the norm in this state. So, unless you have a spouse who is not really fit to be a responsible parent, it's not a position you should take. A common type is Joint Legal Custody. Remember, no matter how much you may have come to dislike your spouse and no matter how justified you may be in that dislike, children need their parents. You know that intuitively and all the studies support that. If a child has two parents, let both parents, if capable, be parents. Allow and encourage your spouse to be involved and to be a supportive and loving parent. Unless you have real justification, you're selling your children short.