It is certainly true that you may not see your children as much after a divorce. You and your ex, if you both have custody rights, need to split up that time. It may be divided 50/50. It may not. Either way, you will not see your children as much as you did during the marriage when you and your spouse were both around them all the time.
However, many parents express concern about not seeing their children again, as if the custody arrangement is going to keep them apart. It does not need to be this way and, in most cases, it is not.
Modern courts usually want both parents to stay involved, and psychologists agree that this is typically best for the kids. It does have some drawbacks, but, on the whole, it is invaluable for children to remain connected with both parents after a divorce. That does not mean a 50/50 split in all cases, but it does mean that the court generally avoids awarding custody solely to one parent and preventing the other from seeing the children.
To do that, the court needs a very compelling reason. If one parent presents a safety risk, that's when they may step in. That parent could have a criminal record, an addiction problem or outstanding accusations of abuse and domestic violence. If the court thinks that forcing the child to spend one-on-one time with that parent would be unsafe, they won't do it.
These cases are in the minority, though. In most divorce cases, there are no safety concerns and they'll try to let both parents have time with their children. That divorce should not keep you from establishing a strong relationship.