((بَارَكَ اللَّهُ لَكَ، وَبَارَكَ عَلَيْكَ، وَجَمَعَ بَيْنَكُمَا فِي خَيْرٍ)).
(May Allah bless for you (your spouse) and bless you, and may He unite both of you in goodness.)
Abu Dawud, Ibn Majah and At-Tirmidhi. See also Al-Albani, Sahih At-Tirmidhi 1/316.