i can relate quite a lot to this. as i’ve mentioned on here before, my ex has quite a bit of her own mh stuff going on, and when we were together i became a sort of unofficial carer to a large extent.
i ended up investing so much time and energy in her wellbeing that i completely neglected my own and it got
to a point where it was completely unsustainable. i had very little social life outside of the relationship and so i never got any sort of respite from it.
i think it’s important to try and discuss it with the relevant people if you are able to. it’s not at all selfish or unreasonable to need some time and space of your own, and if you can find a way to give yourself that, and have an opportunity to recharge a little bit, it will almost certainly improve not just the quality of your life but also the quality of the relationships with those people as well
really hope you can find something that works and gives you the space that you need.