Maybe a new employer?
in the nicest possible way, do you have children of your own? Are you aware of countless families around the country making this difficult decision everyday of having to choose raising 4 small kids vs work or elves existing work.
i am altruistic myself having adopted a 2 yo in my 20s, and would love to step in to raise those angels that you are raising, but even I would know, ultimately, it may come down to me taking in more kids or leaving the job market fully or finding another employer.
if you try, as hard as it is, to remove emotions from this, you might just be able to salvage this. However, at the moment, I struggle to see how you can manage to change your employer’s mind or make them find another solution which you feel suits you. Yup, like another person said, if o was your employer, I would also say no. Sorry,
I know you said they used to say: how will they manage without you. Or such. Sorry to break it to you, what employers say today to suit the situation is rarely what they will consider when it comes to it. Again, remove emotions. Remove feelings of betrayal; and present an objective alternative, if you can, and see. Good luck.