Marriage can be "thought about as a topical political, spiritual, moral, social and cultural" issue (2a in KS3 PoS), one that is undergoing significant change in the UK. However, citizenship education "proper" - that is, Ofsted friendly CE - must link these "skills of enquiry and communication" with the topics in Section 1 of the PoS (rights, conflict resolution etc). Consequently, take care to distinguish CE from sociology or RE, for example. Consider exploring issues such as the role of government within marriage (eg tax incentives to marry, or financial recognition of same sex marriage?), changes in marriage law (reflecting or instigating changes in society?), the rights and responsibilities of married versus unmarried couples (are they different towards children?) or the significance of media coverage of celebrity marriages in society.
Alternatively, democratise the lesson's direction by using parts of the article to stimulate pupils' own questions about marriage (created in groups of four?). Each group's question could be listed on the board, and pupils could vote for which question they would like to use as a class discussion.