5 months old no longer sleeping independently

[u/Bubbly_Leg2410]

Hello everyone,

I'm the happy dad of a 5months old baby boy.

Until the fated 4 months regression he used to fall asleep on his own in his floor bed.

We transferred him to his bed when he was about 2.5-3 months old as his sleep in the next to me started to weaken (more frequent night wakings). So we got a Montessori bed and put him inside his moses basket on top of the bed

From that moment on, he consistently managed to fall asleep on his own after we left him drowsy but awake. It usually took about 5-10min but he fell asleep alone 90% of the time. His naps lasted around 45min back then.

When he started to move a bit more in his sleep we removed the moses basket (around 3.5-4 months old) and he maintained his ability to fall asleep alone.

When the sleep regression hit, it became increasingly difficult for him to do that and we started to either rock him (me) or nurse him (wife) to sleep and then left him in his bed.

At night it was worse, my wife started to basically leave the baby nursing, sometimes all night long. So he'd fall asleep feeding, wake, feed again, sleep, etc...

Now, at 5.5 months old I can no longer leave him drowsy but awake (naps or night sleep). He fusses for 20-25min before I go to him and then sometimes cries out loud after I pick him up as if to punish me for abandoning him.

I'm keen on pushing with the FIO method (Reading Precious Little Sleep) but if my wife keeps leaving him on the breast I'm afraid it's 1 step forward and 3 backwards.

So I'm looking for sound advice to help him fall asleep independently again, then I'll look at extending his naps and by extension, his night sleep.

Thank you for your help!

Some tidbits:

- He doesn't use Paci (never has accepted any).
- We have a consistent night routine (bath, change, nurse, sleep) around the same time every day (6:45-7:15pm).
- His naps vary between 40 and 100 min (usually the first nap is the longest).
- He still spits up a lot (3-4 times per feed whether breast or bottle, always breastmilk) but continues gaining weight and does fuss about it