Do grown (married) children generally attend parents’ second wedding? Is there halachic basis for not attending? Are there other reasons?
ב"ה From what I have read on the subject, the issue of the attendance of children at the second marriage of their divorced mother, is not halachic in nature but based upon a minhag which was not accepted by all. Neither is there a difference if the attending children are married. In the responsa of Rav Chaim David Halevi zt"l (עשה לך רב ח"ד סי' נט עמ' רפז) he offers the possible explanation for the custom not to attend, that when the mother remarries after divorce in other way she is prohibiting her return to her first husband. Therefore, it is in a way disrespectful for the child to take part in an event by which their mother becomes forbidden to their father. However, ( זהב מנחם, חלק ב סימן לו, של הרב מנחם חכם זצ"ל) Rav Menachem Chacham zt"l, says that there is no halachic reason to keep children from attending a parent's second marriage whether of the mother or the father. In his opinion, it is important for children to attend to show their acceptance of what their parent is doing. In any case, even according to the first opinion, should the father, for example, express agreement to the participation of the children at the marriage of their mother, then their should be no reason for them not to participate. Besorot Tovot