As a mother of four the original post in this thread made me smile - and brought back some very fond memories.
My husband and I used to have a similar set-up - two sole accounts and one joint - but, over the years, we have simplified things and use one joint account plus a savings account in my name into which child benefit etc is paid.
The simplest advice I can give you is this - don't panic!! It will all sort itself out as you go along, provided you stay think carefully about your financial moves and your future plans.
I am about to return to work after a break, and it seems I may well be earning more than my husband. This role reversal will take us full circle to where we were when we met! So I would add that (a) there are always options - a new job, a sabbatical, consultancy work from home - and (b) - that you never know what is around the corner, especially when you have children, so remain flexible and forward-thinking.
Apart from that, I would just wish you good luck. I would imagine you will find these forums most useful in the upcoming months!
Cat