The thing is that my current partner wants to try this. She has told me that I need to tell her if "I don't think I can handle this".
She is correct. She needs to know and she cannot be in your head and mind reader. You have to be honest and tell her where you are at.
Are you unwilling to say to her "I want to do this. But I don't think I can handle it LIKE THIS AT THIS SPEED. Could we talk about HOW we want our Opening to unfold?"
Because if you want to be doing this, but find it extremely uncomfortable -- maybe you guys could adjust your behaviors then.
I'm totally making it up here -- but say you want to organize by type of dates. Maybe 1-2 hr coffee/lunch day dates for now since those don't seem to wig you out to the max. Only a little bit. Then next month those PLUS evening dates? Then the month after that -- longer dates like all day long. Then when ready overnights?
Or organize by your before care/after care needs? Maybe you need attention before she has a date or after she gets back? Or maybe you want to know about dates ahead of time so you can prepare or you do NOT want to know sooner than the day before so you aren't chewing your fingernails for a week ahead of time?
You know your own personality and needs best. You don't seem willing to bring them up -- like you guys don't get day dates. You wish you did. Did you bring it up? No. You rationalized that she's probably saving her evenings for you two. Well... that's nice... but it's not giving you a day date you would like to have. But she cannot mind reader you -- you actually have to be outspoken and assertive about making your wants/needs known.
Could sit and figure it out -- be a little more assertive about communication.
It's like you want to do this but you FLING yourself in without a map or feeling like she's the one responsible for setting the tone/pace and your voice is where? Fearful to be assertive because you fear breaking up?
We are aware that our relationship is at risk over this issue. But I do love her as a person, she is extraordinarily important to me and I don't want to lose her. I'd prefer to have tried and failed to have given up because I was uncomfortable.
This is the most loving thing you can do for yourself? For her? To fling yourself into situations that make you feel crazy upset rather than look at it critically and say "No. that does not sound like yummy to me. I can't go there and safeguard my well being like this" and form a different way to go that serves both your needs and hers?
Accepting something is beyond your current willing/able at this time is NOT giving up. It means you are not prepared at this time like THIS.
I couldn't jump off a building at this time. I would have to say NO. If I got a parachute, safety net at the bottom, prepared better with some classes... alright. Then it could be a different answer at THAT point in time.
Another part of me moves towards the thinking that "well, if we're fundamentally incompatible we're going to lose each other anyways right? So what's wrong with trying to find out if it's possible or not?" But your right, I'm into that 'edge' zone in terms of healthiness.
That type of thinking makes no sense to me. It is fatalistic. You "predoom" it and it colors your whole outlook and experience. Then it may very well become a self fulfilling prophecy.
To me it is like...
"Well, if we are al destined to die eventually anyway... what's wrong with jumping off the building right now? " and no thought given to HOW you want to jump off the building or what gear/prep you want to do/have to make the fall exciting and fun rather than fatal.
If you are fundamentally incompatible as dating partners -- you both are not willing to be friends? What's this "losing each other" business? You both prefer to be exes that never speak to each other? Has this been discussed?
A lot of your stuff seems to revolve around HOWs:
HOW to I talk to myself about myself and evaluate my chosen actions. (in harsh ways, less than self respecting)
HOW do we want to Open so all players are comfortable in the journey
HOW do we want to be as exes if this experiment leads to our breaking up
I think you could spend more time on some of those HOWs and see if resolving those helps you relax and feel better prepared to undertake this in a healthier way. You may or may not succeed -- but you can help stack the odds of success more in yoru favor with better preparation and attidude before undertaking it.
Those are just two places, but I'm sure you can find more links.