What you will do when you're ready, you have to pick the date, friday as in after tomorrow, sometime next week, it's up to you, you have to feel right doing this.

Give her a call, no text or email, let her hear your voice on this.

"Hey <insert spouse's name here>, How are you going? That's good to hear. I have something to say and get off my chest, I originally preferred that we work out our difference and get this marriage on track again but the more I think about it the more I see that you're 100% right, it's impossible, totally impossible, it will never work out between us so to that end, I've saved you some trouble and packed your things in boxes and put them in the garage for you. Maybe you could borrow a truck from a friend or rent a moving van and I will load them up for you. Also if you haven't found an apartment yet, give me a shout when you get a chance and if you want a friend to help you look for an apartment, I wouldn't mind helping. I want you to be happy with your new life and I want to be happy in my new life too."

She will be surprised that you packed her things, regardless if she gives you the impression that she isn't.

She will ask why you did this?
You accepted the reality of the situation and there was no use in beating a dead horse, if things are done they're done and it's time for both of you to move on with your lives and to show that there are no hard feelings, you wanted to help her with moving on with her life by taking care of the effort of packing her things and boxing them up for her.

You're cleaning up the place, making it new again and packing her things was an opportunity to get started on painting, rearranging, reorganizing, you know, stuff like that.

You are upbeat and cheerful the whole time.
Even if she gets angry, you remain happy.
Even if she busts a nut and starts mentioning lawyers and legal crap, you just remain upbeat and positive and just tell her that this kind of talking isn't really productive and should be handled by the pro's, you just want to focus on being happy and you want her to be happy in her new life too.

Look if you were fired from your job, would you bother your boss for several months to 2 years begging for him to take you back? Begging, pleading, buying gifts, dinners, offering footrubs, backrubs, and doing work for free til he took you back. Hell No! don't be silly, So you don't need to do this with your wife either, you agree with her decision and move on as well. She will have nothing to fight with you about, nothing to disagree with, you've gone along 100% with her decision and agree that it's the right thing to do.