Your child custody case doesn't have to be a battle from start to finish if your ex decides that you will work as a team for the sake of your children. Being able to do this can benefit the children because they learn what it means to be a productive adult even in the face of challenges. It also sets a good precedent for the remainder of your parenting relationship. This provides more stability for the kids.
As you start to make decisions about the parenting plan, you should be willing to consider any option that is put on the table. You and your ex might not parent exactly the same, but there is a good chance that they are thinking about the best interests of the children and might just have a different thought on what that means.
For some parents, agreeing on the major points of the agreement is the priority. From there, each parent handles minor decisions in their own way. You and your ex might discuss what points are important to both of you. For example, you might feel strongly that your children need to have reading time daily. Your ex might want to encourage a faith-based study group. You can both have what you want, which would be fair.
Just remember that all the decisions you make should put your children first. You can't base anything on what you want or what will make your ex miserable. Instead, put aside the struggles of the marriage and look toward the promising future that you and your ex can provide from different homes.