SEARCH GEM
The Marriage Locator site at www.marriagelocator.co.uk has existed since 2010, is owned by the Guild of One-Name Studies https://one-name.org and is freely available. It is a rather clever site and uses the information based upon the General Register Office (GRO) marriages index, which can be accessed via a number of sites, including FreeBMD. It is ideal for those who are new to genealogical research or reside outside of the UK and therefore perhaps not used to the GRO indexes.
The GRO index provides the name of the individual, the Registration District along with volume and page number and the quarter March, June, September or December in addition to the year.
What you do not know – from the GRO index – is the church or venue of the marriage. It is quite possible, if the marriage took place at a church, to access the parish registers via either the county archives or via one of the online providers should you have a subscription, and should the parish marriage indexes be available online.