Sorry for that tough choice. We had a puppy mill puppy years ago that was jsut never able to adjust. So, Reggie was a mess with her in the household. We ended up rehoming her through United Yorkie Rescue. We waited so long to try again for a sibling for Reggie. Luckily, we got it right this time. And Reggie is actually BETTER and has more confidence now.
Sometimes, it takes longer, and sometimes you can wait for something that will never happen. Only you know what was best for your family. Hugs to you!!