If you and your husband are getting separated or divorced and are arguing about custody, and you cannot agree who the children should live with while the divorce case is going on, then the Court can make an interim custody order. This gives one of you temporary custody until the Court makes a full decision. Be careful about this. A Court will often make an interim custody order into a full one. It can take the court a long time to make it's final decision, and by then it may not want to change an interim order if this is working well.
Access is the right of a child to see the parent who they no longer live with.
The parent who does not have custody of the child will usually be granted access to the child, unless there are very good reasons not to. Usually this means that it can be proved that the child has been abused or treated cruelly by this parent. The Court will need to make an order for access even if you and the father can come to an agreement. The Court will make an order with your agreement in it. If the Court does have to make an order about access, it will either make one that is general or one that is defined.