Hello Space, I just want to echo pps who suggest doing whatever works. When DD1 was around that age I was going absolutely nuts for lack of sleep, and what got me through was eating my evening meal at the same time as her, getting myself ready for bed as she had her bath, feeding to sleep and going to bed myself for the night at DD1's bedtime. Oh, and cosleeping, which meant there was no need to get out of bed. I also, totally uncharacteristically, got into playing games on my phone during the small hours when I sometimes found myself too frazzled to sleep despite being totally desperate for sleep.
DP was unwell for DD1's first year so I, like you, felt very alone and at times deeply resentful, despite knowing that was just how it had to be. I got really upset if anyone suggested that I did something to redress the division of labour, as Baby suggests above (not saying it isn't a valid suggestion, Baby), I took it as a criticism, as if the person suggesting it was missing the point that I would have loved to have different circumstances if at all possible, and as if by rejecting the possibility of challenging the status quo I was forfeiting my right to feel sorry or myself. In your life, at this moment in time, this is how things have panned out with regard to who's doing what. Don't give yourself a hard time about that too. Perhaps think out of the box and see if there is some other way in which your partner can support the situation if sharing nights isn't working out for you. Can he perhaps batch cook on the weekends, or do the cleaning? Shopping? Take your DS out for a long nap in the car so you can sleep undisturbed at home for a couple of hours?
DD1 stopped feeding to sleep at 2, and it was much easier than I thought it would be, because she was finally ready. Still not quite sleeping through, but nowhere near as bad as it was. I've found myself doing exactly the same with DD2 who is 9 months now; feeding to sleep, night feeds on demand, cosleeping (also with DD1) but this time I'm finding it much easier, probably because I know it comes to an end eventually. I wish you all the best, one moment at a time.