Complex sentence: It still is not unusual for brides to live in their parents' houses for a year or so after the marriage, and the children were usually separated from their parents after marriage, except for the first son and his family.
Split into simpler sentences: It still is not unusual for brides to live in their parents' homes for a year or so after the marriage. In the past, children are usually separated from their parents after marriage, except for the first son and his family.