Marriages in Genealogy
For before and after 1837 marriages will be on PRs see Ron's Intro to Parish Registers (PRs)
From 1837 you can obtain Marriage Certificates see UK_BMD Certificates and GRO Index
MCs can be really wonderful - not only the couple and their fathers but the witnesses can be an enormous help. MCs are essential.
Some new data at a fee England & Wales Marriages, 1538-1940 - Ancestry.co.uk
London signatures also has Wills and Marriage Bonds