Can a mother who is not married to father of child keep child away from father with no reason but to hurt the father?

Mother has no reason to keep father away from child but just to hurt the father because he wants to see child and spend time with his child. Mother refuses to let him see child. Mother will say father can see child then change her mind a few hours before bringing child over. Mother lives with another man who is not child's father but the child's father has his own place and mother still won't let father have visitation with child. There is no court dates or even lawyers involved.