BG- The basic Halacha for men is that they have an obligation to learn Torah every second. But they are allowed to stop learning for any Mitzvah that can’t be performed by someone else. If going to the chasuna was a Mitzvah that couldn’t be performed by someone else, then it was allowed.
I assume that usually when people go to chasunas it is for the purpose of being mesameach the chasan and/or kallah which is a Mitzvah that can’t be done by someone else.