mrsmc yes I agree, it's a very western idea (particularly UK and USA) that babies and toddlers should become as independent as soon as possible because our cultures values independence.... Interestingly we have some of the highest numbers of mental illness in childhood....
Babies are supposed to want to be close to mum, as that article shows, its down to basic physiology and neurobiology.
I went round in circles for the first 6-7 weeks of DDs life trying desperately to get her to sleep in her cot instead of attached to the boob (what she wanted) because I was made to believe it was what I 'should' be doing and I was always told that cosleeping was a no no for SIDS. Mainly I was confused because my instincts were telling me I blister to my baby and give her what she needed (along with what I had studies about cognitive developmental neuroscience and attachment in my degree) but extreme sleep deprivation (DD had cmpa, silent reflux, soy allergy, TT and colic!!!) and an interfering DM and MIL I couldn't think straight.
When I stopped trying to fight against my DD and just give her what she wanted then everything got easier.
I think so much of what makes sleep deprivation so much harder is Unreaslistic expectations. Western cultures are obsessed with babies sleeping through and sleep is a billion pound industry.... If that many babies have 'sleep problems' then maybe our expectations are just wrong??
Also, when you actually start to look into safe cosleeping you realise that it's not dangerous if done safely and in fact research suggests safe cosleeping with a fully breastfed baby is actually protective against sids.
There are sleep regressions at 4 months, 8-9 months, 12 months, 18 months and 2 years (thereabouts)... Sounds like you're currently enjoying the 9 months one...??
I'll attach some links you might find helpful ...
This too shall pass!!! 