Hoju, You can tell her you need time to decide if now is the right time to file. Ask for 2 weeks and settle for a week. I agree with toots. When you do give her an answer it should be similar to "this is not what I want, but I respect your decision and will not stand in your way"
Regarding the finances: Smart move. If you have a LOT to lose financially, you might consider agreeing to file right now, that way she cannot change her mind. I don't know the exact numbers but your chances to R are about the same regardless of the status of the legal filing.
In my sitch I am pushing to file quickly because she has been making changes to our original agreement and I am trying to protect my finances and my 50-50 time split with the boys. Once it gets filed she cannot make any more changes.
M42 W40 T17 M15 S13 S11 BD 7-14 A discovered 7-14 WAW moved out 10-3-14 D final 2-23-15