On top of sleeping, I like to add eating as very important to your own perception of how good a parent you are. :D

To be honest, with my two kids, how much they eat influences their sleep heavily as well. Unfortunately, my first has always eaten too little (he'd happily have his broccoli too, but never enough to be consider him fed), and the second is very picky (she eats a lot of what she likes, none of what she doesn't). When they eat well, they usually sleep well too.

Out of my very limited anecdotal experience (two small children), it mostly relates to how well fed they are: unfortunately, both of our two kids are bad eaters (the first just wouldn't eat enough, ever, even today at 5yo; the second is just extremely picky but eats plenty of what she likes). The older kid kept waking up in the middle of the night even at 3 yo (not to ask for food, but when we were sure he got stuffed in the evening, never did he wake up). The younger slept through the night at 10 months a few times, but as she gets pickier, those are actually less frequent now at 15 months than back then.

I am sure we could train them with some sort of food scarcity approach (this is the only thing there is to eat; now is the only time you can eat) to teach them to eat enough of the food that's there, but that'd take a psychological toll for a few weeks on us that we aren't able/willing to take on.

They have training centers for this now? I'm genuinely horrified. I'm aware there are different meanings to "sleep training" depending on who talks about it, but the way you imply they use the term ("stop going to them", i.e. let them cry it out) it's just a cutesy way to say "neglect".

There's a reason parents pick up this version (i.e. the "let them cry it out" version, not the "create a safe and comfortable environment to allow them to self-regulate when they wake up" one) of so-called sleep training from books, "experts" and now apparently also training centers, whereas co-sleeping needs to be actively discouraged to stop parents from doing it intuitively.

I'm not saying every parent who doesn't co-sleep with their child is engaging in child abuse, but many mainstream forms of "sleep training" (especially the informal ones) very much boil down to "neglect your infant until they learn not to broadcast their needs because nobody will take care of them".

I'm also not saying that OP's account is representative of all co-sleeping parents. Co-sleeping (with breast-feeding) simply allows for reducing interruptions from nightly feeding in a way that is hardly replicable without it.

Really sorry to hear that. We had a nightmare scenario at about 11 months where she howled all through the night and my wife cried pretty hard too as there wasn't anything we could do. We cut a trip short and just drove 5 hours back home (the next day) to get our daughter back to familiar surroundings if it meant sleep for us. She then slept through the night and more or less has done that since. We felt so much better, although I remember checking in on her often to make sure she was ok as she'd never slept that long. I really hope you catch a similar break sometime soon. It might also help when they start to get a more varied diet that isn't just milk, so they aren't always hungry if that makes sense (I'm definitely not any kind of expert though and not giving advice).

Hang in there! It won't be that way forever.

The way my wife and I had it with my first was for me to start taking care of my boy at 6am when he wakes up and let her sleep until 9am every morning, when I'd start work (from home). If you can find a time where the boy does not need her (eg. those times when he's fussy but not hungry), that's the best you can do.

Sometimes that's not an option, but this worked great with our first (we couldn't do it with our second, so my wife is more of a zombie this time even though the daughter is a better sleeper on average).