Absolutely shocking and I feel for you. If you have got flights and hotels booked, still contemplate going and spend the night in Taksim and watch in a bar. For sure you will see the game together, you'll still be able to say you went to Istanbul and also have a memory. In your situation I wouldn't fancy enduring that stadium and fan zone experience with children, even if our seats were guaranteed to be together. It will just be thousands of fans, nowhere to sit, no shelter from the sun, overflowing portaloos, and expensive food and drink, and that's before a shite view of the match! In fact even as I write this, I'm convincing myself to not bother buying a match ticket and just have a great day in Taksim instead.