Related על ברכות 2:8

The grooms and all [others] who are involved in [other] Mitzvot (commandments) are exempt from reading [the] Shema and from [the Amidah] prayer and from Tefillin (phylacteries), as it is said, “… when you sit in your house”, (Deuteronomy 6:7) which excludes grooms, “and when you walk on the way”, (Deuteronomy 6:7) which excludes those who are involved in mitzvot.

Best men and bridesmaids, and all [other] wedding attendees are exempt from [the] prayer [of Shmoneh Esreh] and from [putting on] Tefillin (Phylacteries), all seven days [of the wedding celebrations], but [they are] obligated in reading the Shema. Rebbi Shila says, “The groom is exempt [from saying the Shema, Shemoneh Esreh and putting on Tefillin], but the wedding attendees are obligated [in all of them].”