I think so long as you have a friendly relationship, and you know the animals will be safe with him, there's nothing wrong with it. Where I could see trouble would be if these passings back and forth caused you emotional distress, or if he kept on trying to interject himself into your life, causing problems with your emotional state or future relationships. It might also be a good idea to put an agreement into writing, and have it notarized.
That way, if he ever decided that "hey, you've really pissed me off this week, so guess what? I'm keeping the dog! " you could take him into court and show the judge your agreement, clearly stating that he is to return the dog to you, and that visits are at your discretion.
The dog is legally "property" and you want to be able to clearly prove that you are the owner, should the worst happen.
I'm not married/divorced, but if I was, I would not let the ex see my pets.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.