An intervening period of time is one that separates two events or points in time. During those intervening years Bridget had married her husband Robert
An intervening object or area comes between two other objects or areas. They had scoured the intervening miles of moorland. time that passes between two events
standing between or separating two objects or areas; "Paris--where the same city lies on both sides of an intervening river"; "after reaching the top of the hill he looked across an intervening meadow to another line of hills"