I can't see any point of online divorce when it's possible to buy a book explaining the basics and download all the forms free and I agree when there are no children or finances it is possible to DIY. However, over the years I've seen so many people get into a mess, sometimes over small detail, it's not something I would normally recommend. And before anyone says anything, yes, I know sometimes lawyers stuff up too but in my experience it isn't nearly so often or drastic.
I think consulting a lawyer early on to find out where you stand and what your options are is a good idea. Also negotiating through a third party can be useful if you can't come to an agreement and mediation or collaborative law doesn't help. A lawyer can draft a consent order which once approved by the court is turned into legally binding settlement. I agree with Mike at least consider the possibility of getting legal advice as to whether your agreement is a fair one.