Well, getting back 3 is a lot… not the norm. But with experience you learn to weed out the bad owners.
Show homes are not worse than other homes-- a GOOD show home wants a pet AND show dog, not a show dog. A REAL show home is experienced and the behavior issues would probably not have come up.
I am sorry for what you have gone through-- but let me make a suggestion if you do decide to breed again. Make calls regularly. Constant contact, at least monthly the first year, helps to be on top of things so you can help new owners as things go along instead of get a dog back once the issues are at the "get the dog out of here stage." It gives you early warning of a bad placement so you can suggest rehoming instead of losing a lot of time while they put off doing what your gut tells you is coming.
And give yourself a HUGE pat on back for getting them back. However bad it is to get them back, having one go missing or finding out they dumped the dog and no way to trace is would be much worse.