The marriage registers often have two marriages to a page, so there may be four people referenced under the same volume and page. Older registers may have more marriages per page, and the volume and page reference can relate to six or even eight people. That is why when you search for a marriage, you may often see the result, "Fred Smith married Jane Brown or Sally Grey". It may be necessary to find a copy of the original register image to ascertain which was the correct spouse for Fred Smith, but depending on the dates involved a subsequent census entry, or several, can often help confirm which was correct.
As maddys52 has said, if searching via FreeBMD the page number is linked, and clicking on it opens details of the full entry, which shows all the names on that page of the register (but still doesn't show who married who). So further investigation is often needed to work that out, unless you already know the answer. Census entries, searches for baptisms under the father's surname within 10 years of the marriage date, etc. can often disclose the wife's first name.
