I'm not familiar with Arezzo in particular, but have been to Tuscany and Italy multiple times. The answer depends on the type of trip you want. Option 1) Leave with kids with other family and you and your wife go by yourself for a week or as long as you can swing it. You will have a very enjoyable vacation with your wife. Option 2) you bring the kids because you want to get them international exposure at a young age. But you will have a family trip which =/= a vacation. There is not a wrong answer as it just depends on what you want. But I seriously doubt there is anything kid friendly about Arezzo besides the normal joys of Tuscany…like great views, great wine, great food, great history, great art, great cafes…all the things that kids have a difficult time appreciating.