When to let your guard down? How about when she commits 100% to fixing the marriage instead of walking away when SHTF? I too am dealing with a wishy-washy WAW who one minute sends me emails talking about past vacations and how much fun we have, then the next is demanding a divorce. I am currently getting a life without her, she is aware of my activities and it's driving her nuts, she is voicing it to other people. I know why too, because said activities are completely out of my normal comfort zone. BUT that is why I am doing it, for myself not for her. I am working on getting comfortable in my own skin again and not being an "us".
So keep doing things for you, keep working on you, you can do it. Don't play the game, don't let her keep getting your hopes up only to crush them a second later. Be positive, be smart and be happy.
Me: 38 W: 32 S10 D6 T: 10 (02/2004) M: 7 (12/2007) Separation 02/2015 OM confirmed 01/2015, D mentioned 12/2014 D finalized 9/2016