So I guess I just don't get S. You're in or you're out, I think.
And she is familiar with this side of you. You have assured her numerous times where you stand. So, she's very smug in her situation. Maybe you need to create a crisis for her. That's what I'm saying. Try to look at this as not being for your opportunity to live as though you're single, but rather it is for her to see you being available to date. It would be a last resort, don't you think?
I understand about not paying for the house and an apartment. If you consider leaving the impression that you could possibly be meeting a female friend (don't have to identify it as a date), an in-house separation might work to your advantage here. Ordinarily I am not in favor of in-house S, but in this case, it might work.
Being mysterious would be key. She doesn't want a "courteous call", she wants to keep tabs on you! So, you just say "I'm leaving" and when she starts in with the questions, you say IDK.
You say that S to you looks giving her permission to do what's she's already doing. But you are only seeing it from one side. Maybe she will see that S as give YOU permission to do what you wouldn't do otherwise.
As for your timeline, what difference does it make? The S ends when you planned to end the M......or when there is a reconciliation, whichever comes first. Unless you know of a better last resort. At least this way could not be considered passive.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!
