It depends what grounds are being used for divorce. If it is two years by consent - agree to provide your consent only if he agrees not to make a claim for costs.
If he issues based on unreasonable behaviour your disputed over costs is more difficult to call. One judge might say \"ground for unreasonable bahaviour is proved, costs should be paid\", another judge might split if 50:50 or set a fixed sum and a third judge might disallow costs depending upon what you say.
If the petition
is issued with a claim for costs, you can specify on the acknowledgement of service
that you do not wish to defend the petition but that you oppose the claim for costs.
The best bet is to speak to your ex ASAP to agree a strategy. He might not be that fussed in which case you can agree to cooperate with the process in order that he forego any claim for costs.
Once the petition is issued with a claim for costs it will have to be amended to delete the claim at a later date which is simple (and the kind of amendment that requires no additional court fee) but can be avoided with prior agreement.