I’m afraid
@Agzy my suggestion won’t go down well with Pauline - but will meet your needs and hers in the long run.
I suggest you keep the place and keep taking Pauline as you were doing PLUS organsising her son to take her out for a few hours per week.
that way you get more respite and Pauline gets used to more people helping with her care. I know that’s not what she wants and will protest but being frank will be needed in time.
Otherwise as you say I fear it will not end well for you and in the end Pauline as you are likely to need to rest for your own health at some point.
Easy for me to say though not having to implement myself!
Ps did you ever get a carers assessment?