Q. Someone in my family is getting married on the day after Pesach. (they keep the minhag of beginning the prohibitions of Sefira from Rosh Chodesh Iyar). Does the Chassan fast on Issru Chag?
A. Mishna Berura (429: 14, quoting Magen Avrohom. mentions the accepted general tradition of not fasting on any Issru Chag.
Poskim mention that that even a groom on the day prior to the Chupa does not fast specially on the month of Nissan.
Rabbi A. Bartfeld as revised by Horav Dovid Pam, Horav Aharon Miller and Horav Chanoch Ehrentreu Shlit’a