Between the laws of levirate marriage, marriage contracts, divorce, and betrothal, the Talmud has more to say about the subject of marriage than virtually any other topic. Even Shabbat, the subject of two lengthy tractates in Seder Moed, is not so productive of laws and legal debates as marriage. This makes sense, because while Shabbat is the holiest day in Jewish life, its laws are commandments, not subjects for negotiation. When the rabbis say that Jews are not allowed to perform 39 categories of labor on Shabbat, there is no way for Jews to bring God to court and argue with Him about exactly what He intended. Marriage, on the other hand, is understood in Jewish law as a contract between two parties, the bride and the groom, which means that it is capable of endless refinements and disagreements. Indeed, when talking about marriage law, the rabbis laid down many rules that can apply to any kind of contractual agreement—rules having to do with intention, agency, conditionality, and other complex matters.As I've said before about various Talmudic matters, it's complicated.
Earlier Daf Yomi columns are noted here and links.