A delivery device includes first and second housing portions that selectively engage and disengage. A reservoir on one housing portion operatively engages a drive device and/or a needle inserting device on the other housing portion. Upon proper engagement of the housing portions, the reservoir operatively couples to the drive device and/or the needle inserting device. A first magnet on the first housing portion and a second magnet (or a magnetically-attractive material) on the second housing portion are positioned to magnetically interact with each other, upon operative engagement of the housing portions. A third magnet on the second housing portion may be opposed to the first magnet to help align the housing portions for connection. A magnet-responsive device may be on one or both housing portions to detect alignment and/or connection of the housing portions.