I have been with my partner since my ds was under 1. DS is now 3.
DP's salary and my salary are paid into my account. I pay all the bills out of it, shopping etc anything we need etc etc, treats for me
DP gets a small amount of child maintenance paid into his account (his ds also lives with us). I only ask for this if we are skint, otherwise dp uses it for whatever (very small amount anyway).
Money has never really been an issue tbh, we've either got it or we haven't, as long as the bills are paid. Anything thats left over, we usually go to a concert or do something together.
As far as ferrying ds to childminder etc, this mainly falls on dp, due to the fact that he drives and i don't.
Also I work on a shift pattern, so dp will babysit and its basically whoever is not at work will take responsibility for the kids.
We became a 'proper' family unit definetly the minute we all moved in together if not before, as there as a lot of planning etc before we moved in, im sure his salary was paid into my account the month before we moved in together (just getting him used to having no money
His DS is less of an issue for needing looked after as he is a teenager (although he certainly needs more money to keep entertained )