Welcome to the board, and to the joys of owning a cavalier.
I'd suggest looking for a reputable breeder following the routes suggested in the Library section of this site (In the US, AKC registration is only the bare minimum to look for -- or CKCSC registration -- and does not guarantee a good breeder or carefully bred dogs, sadly). There are a couple of reasons why. First off, any reputable breeder would have had a line in the puppy's contract that stated clearly that the dog must ALWAYS be returned to the breeder, never rehomed without the breeder's permission. You could possibly face a breeder demanding that he be returned to him/her. You could also innocently create problems for the family that decided they wanted to rehome him, including a legal situation.
Second: to be honest, I think the above situation is unlikely to happen because the chances are probably small that Roscoe came from a breeder you really would want to revisit for another cavalier. This is not a criticism or put down of Roscoe but just practical information -- many of us have cavaliers from unknown or so-so backgrounds, whether rescues or dogs we got when we didn't know any different and they are all wonderful dogs that we cherish
but we definitely don't want to patronise breeders of that sort ever again because they slowly damage the entire breed with their poor breeding practice. Cavaliers from good breeders who focus on health and careful breeding are costly -- we'd be talking a minimum of $1500 at the low end in the US and on up to $2500 or so for pet quality dogs -- and people generally are, except in the most unusual circumstances, very unlikely to rehome them just as most people would not give away a car or other investment. If for any reason owners need to return the dog they generally have good relationship with that breeder and would contact the breeder about having the dog go back to him/her and perhaps resold. Not always, but certainly most of the time.
Also: this is a breed that does have some serious and potentially very costly diseases that become increasingly widespread because of casual breeding for a pet market by people who know little about genetics and are not breeding good quality dogs. Breeding isn't just about buying nice dogs but about understanding generations of pedigrees and knowing what the strengths and weaknesses, in appearance, temperament and very importantly, health are on both sides of the family. An outwardly healthy dog can easily produce severely ill puppies with long term health problems. Sadly, the vast majority of cavaliers do not come from good breeders -- most come from mass breeders (Puppy mills, as depicted recently on Oprah), pet shops (who buy primarily from mass-breeding puppy mills) or people backyard breeding who know nothing about proper breeding. All these sources perpetuate illness in purebred dogs, with their very narrow gene pools.
Hence, if you find Roscoe came from a good breeder, there's a possibility of losing him or causing some difficulties for all involved. If you find he came from an indifferent breeder, you might feel you would have been happier not knowing the specifics and just treasuring the new addition to your home. So that's why I'd give the advice to enjoy Roscoe and all the pleasure he brings
, but to find a reputable breeder for a second dog, or perhaps a rescue from breed rescue.
