First time commenting on a another person's thread so please bare with me...
I really understand where you are coming from. The bit you wrote in journaling I could have written word for word this morning as well. Coming up to Christmas is a particularly difficult time as it normally is such a happy family time...my kids and I have decided to do something completely different than normal this year so hopefully it will help. However, there will be a huge void where my H should be!
As far as getting a puppy...my H and I got a puppy ten days before BD and if I had to do it over, I would not have gotten him even though he is a lovely dog. My kids are a bit older than yours and were away at university so I was left to try to look after him and try to train him...I was in no shape to do that so he still pees on the floor every night even though he is now a year old. Every morning I step in a puddle:) Having said that he is a huge comfort/distraction for my kids...so maybe rescue dog that is already trained would be a better option...