You're right, this is a conversation you need to have when you're ready and definitely not at work. It can even wait a day or two until you're sure you're ready.
Just remember to stay calm and polite. Talk to her as you would a neighbor, friendly but not emotional. If she gets mean or tries to engage you in a fight just say you'll let the lawyers handle it and politely end the call. If she asks what you've been doing then allude to a busy life, mention a few activities with friends. Don't ask her what she's been up to. And remember this is not the time to ask her why she hasn't contacted D11.
If you love somebody, set them free. http://tinyurl.com/2empx2g