For some parents, the decision to move forward with a divorce is put on hold until their child reaches the age of 18 and leaves for college. Parents may decide to push off their divorce until their kids have left the house for many different reasons. For example, they may not worry as much about how their divorce will affect the child now that they have reached adulthood, and issues such as custody and child support may not be a concern, either. That said, all sorts of challenges can arise for parents who decide to split up once their kids have become legal adults.
A child may no longer live in their parents' home, but they could still be affected by their divorce in various ways. For example, the divorce could place additional strain on them during college and they may still have a very strong emotional attachment to their parents' marriage. However, you should not decide to cancel your divorce solely because of how it may affect your kids.
There are various reasons why divorce can be less complicated when all of a couple's children have reached adulthood. Aside from emotional maturity and independence, some have an easier time discussing these matters with one or both of their parents. You should try to help address any of your child's concerns and it may be helpful to explain the situation to them.
Every marriage is unique and there may be certain family law issues that you need to review before filing for divorce.