Divorce is the end of your marriage. That doesn't mean it's the end of your relationship.
Remember that as you move forward with this process. You will likely still need to deal with your ex from time to time. It may be very consistent. You may never fully move beyond it.
For instance, perhaps you have children together. You're still their parents, even when you're not married, and you may share custody. One of you may, at least, have a visitation schedule. You need to work together to figure out what is best for the kids and to schedule out your lives.
You may also share legal custody. This means you have to talk about things like where the kids go to school or what medical treatments they get. Big decisions are something you have to work out together, in accordance with the court order.
There's also the financial side of things. Perhaps you get a pension. Your ex may be entitled to a portion of that pension, which gets paid to them every time you get paid. Maybe you have to make alimony payments or child support payments. These things keep you tied together financially, whether you're married.
As you can see, these are all potential points of high conflict. The way that you each deal with the children or with money may have played a large role in why you got divorced, and yet you may need to keep doing it even after the split. Make sure you understand your rights and where you stand from a legal perspective as you work this out.