Quote:
I have come to the realization that my boundaries and limitations are impossible for him and the bar too high.


When we make boundaries we make them for ourselves more so than we do for our partners...
Maybe they are too high for him...but, as he has moved out, is seeking treatment, and wanting to come home...

He does need to show, actions do speak louder than words, over a long period of time that he is willing to do what it takes to get to where he wants to go...home.

So, what happens if you relent? You show to yourself that your boundaries are meaningless...you will cave...give up...before he has completed enough treatment to be steady enough, regular enough, to be trusted.
What do you show him...pretty much the same you show yourself...except, one thing...you live inside yourself, not inside him...you have to live with your decisions, as he does his.

So, the boundary is not wrong, or too high. It is right for where you are at this time. You may need to discuss with Your Therapist how long this will/may take for him to get to some sort of equilibrium...what things, in detail, he will need to succeed at...for instance...staying on a good medication cocktail once found...for a long period time...seeing therapy for a goodly time...having his therapist, pdoc, Your therapist discuss whether he is ready to come home...and whether You are ready to have him home...

While he is gone...and working on his own problems...this is the time...THE TIME for YOU to be working on issues you have, as WE all have, that come from his illness...from before you two got together, from long before meeting.
This will help affect how you respond to him/others...so, instead of reacting to his outbursts, you can respond to the underlying needs instead of the irrationality...btw, most irrationality is based on some rational need, expressed wrong or incomprehensibly.
Anger, frustration, crying, deep sadness over what we think of as trivial or irrational may have a real reason for being there...just not the one we think we see.
*This is an disclaimer...nothing in the content of this or any post is of real people...this is hypothetical.