If your spouse contests the petition this could increase the cost of your divorce proceedings. However, this is not especially common.
Potentially, where most of your costs will lie is in the separation of your finances. Sometimes it is possible to agree your finances with your spouse relatively quickly and therefore your costs will be quite small. This can be done between yourselves, through solicitors or through some form of mediation. However, if you cannot agree and end up going to court then your costs can rise rapidly.
You can only go to court to resolve your finances once the divorce petition has been issued. Both parties will need to make a full disclosure of their financial situation.
Usually, up to three hearings will take place: the First Directions Appointment, the Financial Dispute Resolution and then the final hearing. The purpose of the first hearing is to decide if you or your spouse need any further information, or if the court needs any further information, before the negotiations can begin. At the second hearing (the FDR) the judge indicates what they think is fair and both parties are encouraged to reach an agreement. Most cases are settled at this stage. If both parties cannot agree then the final hearing will take place and the judge will give the final order after both parties have given their evidence. It is worth noting that what is seen as fair in one case may not be fair in another and, although the judge must take into account the factors in Section 25 of the Matrimonial Causes Act 1973, it is case law that provides guidance on the interpretation on this.
Both you and your spouse can claim for income, capital and pension provision. The more complex your financial situation the more lengthy the process can be and the more the costs can rise.