Thanks, 75, for providing thoughts upon which to reflect. Fans through the decades have no choice but to move on, but some cases are never easy... or like you suggest, some are just never, period.
Posters can insist and implore we move on, but it's not an instantaneous process for everyone. Especially while we languish in suckitude, and our ex is dating the quarterback of the football team, parading around the class party. That's a scene best to not attend.
In the meantime, we research the rescue sites, looking forward, to get a new dog -- not to replace an old bud who passed on, but to get back that old sense of companionship... and familiarity.