Giving her the space she’s asking for will help her to clear her mind, and make a decision about the future with hopefully a bit more clarity. Trying to pull her back in this scenario is just putting more pressure on her to make a snap decision, when it’s likely she has a lot of things to consider.
I know it must be scary for you, too, however; I’m not going to criticise you for trying to grab the life ring when you feel as if you’re drowning, so to speak.
As hard as you might find it, as Bill3 says backing off a bit will show her you’re listening and respect her wishes; it would demonstrate you’re not solely focusing on what you want. If you have any chance of saving your marriage that would work in your favour. And, if not, you can say you did everything you could under your particular circumstances to make it work.