OP, not a specific friend, but just the tapering off of friendships in general that we had made during the infant/pre-school years. Bit by bit the playdates and bday invites become less frequent and are not reciprocated. Our days at the pool are spent more alone, and DS is not "one of the gang," even though others he knew somehow are. I enjoy our time of course, but I feel lonely for him and myself.

Fortunately I WOTH and have a good set of friends through work, and they in turn have known DS since birth and care about him dearly. Where possible, I try to match up him with some of their grandkid visits. AS an AS kid, he enjoys these adult friendships as well.