I have always told clients that "the other party will be an ex-spouse
but will always be a co-parent" -- i.e. try to minimize the strife for the benefit of the children -- sometimes difficult to do but well worth it in the long run.
I agree with Caj that the more you can agree on (child custody/visitation, child support, community property division, etc), the less expensive it will be, attorney's fees wise. Most attorneys will try to help you minimize costs -- just have a frank discussion with them about fees and your expectations. You can control what you pay.
I agree with Caj and respectfully disagree with Longranger -- do-it-yourself divorce kits are usually useless because everyone I know that has tried to use one, still has questions that only a lawyer can answer -
what are the local court rules, what domestic motions can be taken up during motion hour, is there a domestic magistrate assigned to the judge, etc. -- there are also books you can buy on how to do emergency surgery, but most reasonable people will go to a competent doctor. Most important, you can simply Google your state's domestic/marital laws or go to the public library and read the statutes,
without the cost of buying a book.
In our jurisdiction, couples are required to attend a court-sponsored
anger management class -- it actually works -- see if your local court has that service. Also, consider mediation of any thorny legal issues --
mediation is a very practical and cost-efficient/cost-effective method
of resolving domestic issues -- they must be qualified under your state's mediation statutes -- in our area, domestic mediation costs average $35-40 an hour, which is a fraction of what usual hourly rates are for attorney fees. If the mediator successfully resolves the disputed issues, papers are prepared and signed to acknowledge the agreement between the parties resolving the disputed issues and said agreement is included in court orders issued by the court.