In my situation yes I wish I'd D'd her the first time I would've been much better off both financially and even emotionally by now. Hindsight is 20/20 but even then there were some positives in our reconciliation especially when I think about DD. She at least got to experience some family stuff and build some fun memories that she'll cherish for the rest of her life.
However, I like that you're looking at things objectively. Since you can't file for a while that's a good thing actually. You're in no rush and you can use this time to detach and focus on yourself. Figure out how you want the D to go and use this time to research the laws and attny's while you have the time.
As for her flirting etc...could it be that she's simply being cordial and you're reading too much into them? Even if she is you decide how you will react to them...or won't. Setting boundaries is good and you should definitely do that but you can't tell her 'STBX next time don't ask me if I want a coffee!' instead you just politely decline 'No thanks. Are the kids ready to go?' - your focus should be the kids nothing else.
Now if she does do something that over steps the line then clearly you should tell her not to "That's not appropriate, please don't do that." etc.
You have to stay in control of your emotions and it's important to treat her with the same level of respect and courtesy that you would expect from her- if nothing else for the sake of future kids dealings.
Me: 35|WAW: 38|D: 6yo | http://tinyurl.com/2dxx7m6 Feb 2006, left, came back in two weeks Aug 2006, left again Apr 2007, filed for divorce Dec 2007, reunited Mar 2010, moved out, filed again