Hey OP, solidarity to you our worst time of sleep deprivation was when baby was around 4/5 months old and I swear I still have a bit of trauma around it and anxiety around it going back to that so I can fully relate to how exhausted you guys must be feeling.
Loads of posters here saying “totally normal for bf baby to still wake during night” and essentially telling you to suck it up / buckle up for a long ride. I’m going to be totally honest now and give you our scenario but it’s not to make you green with envy at our sleep situation, it’s genuinely to let you know it doesn’t necessarily need to be this way for you if sleep deprivation isn’t working for you.
Our baby is nearly 9 months now, and I exclusively breastfed up until 8 months. Never a great sleeper, and around the 4/5 month mark was the worst, up feeding 3-4 times a night. So the most we would get was maybe 3 hours of sleep at a time.
Now our baby is nearly 9 months and genuinely (honestly) sleeps from 7pm - 7am. We sometimes have to go in to pop a dummy in but its quite rare we need to do that, and usually only once a night. Not saying this as a boast or brag, it could totally all go to pot for us and I could be back in the zombie camp with you, but I didn’t think we would ever sleep again and now we genuinely have a baby that sleep 12-13 hours a night.
this is what happened for us:
dummy for sleep, blackout blind, white noise
moved into his own room at 6 months
at just over 6 months I stopped breastfeeding during the night, apart from a 10.30pm dream feed. That dream feed was the last bit of milk he would have until 7am, and any wake ups after the dream feed would be met with cuddles and dummy and shushing back to sleep (some nights this took ages, but we held strong on not giving milk overnight). I was happy to do this because he was eating like a champ, 3 meals a day plus snacks.
at around 7 months we introduced a big bottle of formula (210ml) as his last feed before bed and I then felt confident that I could stop the dreamfeed which I did at 7 months.
So at that point baby is down to 1 breastfeed in a morning, 3 meals a day and snacks and water, then bottle of formula before bed.
At 8 months I replaced the morning breastfeed with a 210ml formula for breakfast. This has been us for the past month:
210ml formula for breakfast
porridge
mid morning toast and peanut butter
lunch (usually scrambled eggs, spinach, cheese)
mid afternoon snack (usually baby bel and finger food veg)
dinner (usually meat / fish / veg)
210ml formula before bed
for us I think it was ensuring he is really well fed throughout the day to give me the confidence and reassurance that he doesn’t nutritionally “need” the milk overnight anymore
and then teaching him that night wake ups won’t be met with milk (again, could be some long nights there initially but we held firm on only giving cuddles / dummy / reassurance but not milk and eventually he gradually just woke up less)
this might be way more info than needed and every baby is different but loads of people say sort of just accept sleepless nights as par for the course, when it’s damaging your mental health (which sleep deprivation absolutely does) then I also needed to hear that there was another way!
Your partner is an absolute champ for still breastfeeding, and she must be knackered. She might love breastfeeding but she might want to sleep again, if she is ready I would absolutely stop feeding through the night and go from there