Does your ex. live with his parents? My son lived with us for about six months following his separation and he saw his children regularly at my house. There were no problems with that as far as I know and it seemed to work very well.
To answer the question contact centres provide a safe, neutral environment away from high-conflict situations so that children can see the parent who does not live with them or other family members, such as grandparents. It can be difficult finding a place at a contact centre and different centres have different facilities, and there is a charge. Sometimes a contact centre is just a venue for dropping off and collecting children. Other times contact maybe supervised by the staff at the contact centre to ensure contact is safe. In most cases using a centre is just an interim arrangement whilst contact is sorted out.
Some parents use a contact centre because they cannot agree contact arrangements and have difficulty in seeing each other. In these circumstances a contact centre enables some form of contact when otherwise it wouldn''t happen and helps prevent the situation from becoming overheated. Witnessing arguments and outbursts of temper at handovers or contact is not in children''s interests and can damage the relationship they have with either parent. Children learn by example and if the communication between parents is negative the children tend to be unable to communicate well in their relationships when they grow up and tend to have dysfunctional adult relationships.
Alternatives to contact centres include arranging handovers or contact in neutral public places or through third parties. For example, if a parent has never lived with a child and the child needs to bond the parents could meet at a play centre. Contact may take place at the home of a friend, family or neighbour. Handovers could be in a supermarket car park. That may avoid time and expense traveling to a centre and the charge.