I would advise that the first thing you do is to visit a solicitor, perhaps together if you are being amicable. Ask the solicitor to draw up a 'Deed of Separation' - this will allow you to agree how your finances will split, and it can also contain a clause asking the divorce court to dismiss any future claims which you may make against each other on the grounds that this agreement has already been made. My ex-wife and I did this, with a 50/50 split and, because there were no children involved (our son was already 22 y/o), the divorce went through very quickly (I filled out all the forms, myself, in my wife's name).
I don't remember the solicitor's fee exactly, but it wasn't very expensive. That, and the court fees for the divorce petition (about £400), were the only costs involved.
I guess that the only reason there may be for the arrangements in the Deed of Separation to be questioned would be if one of you then becomes reliant on public funds.
