Civil partnership registration was available to same sex couples from January 2011 to November 2015 when it was abolished after the successful marriage equality referendum.
Many couples married after the change in the law but many did not and if any of these relationships fail an application for Dissolution must be made to the Courts. The same applies to same sex couples who registered a civil partnership abroad.
Despite the successful marriage equality referendum same sex couples still need be careful and get sound legal advice especially in relation to any children they have as the non biological parent may not be automatically entitled to parentage rights.