I was writing an article earlier in the week and I had included some information about Matrimonial Investigations. These were done by the Catholic Church prior to a couple getting married to make sure they were eligible to be married, i.e., not bigamists, not related, etc..They hold much more information than the usual marriage records.
For those with early California ancestors there is a collection of Matrimonial Investigations for the San Gabriel Mission, though it does include other missions, at the Claremont Colleges Digital Library located at http://ccdl.libraries.claremont.edu/collection.php?alias=mir. These are the original records digitized from the 18th and 19th century.
I found one investigation in a copy of the United State Catholic Historical Magazine available from Google Books at http://books.google.com/books?id=3Sg2Nzj_L3YC&pg=PA195&dq=matrimonial+investigations&cd=1#v=onepage&q=matrimonial%20investigations&f=false. This is from an investigation from Florida, translated from the original Spanish. It provides a lot information about the couple and their parents. In this example, the mother gives permission for her son, who is a widower, to marry his new bride. It also includes information about the grooms first wife.
This magazine is worth a look at, it includes a lot of great historical information back to colonial times.
To find matrimonial investigations, I would recommend asking at the Catholic archive where you are requesting records. Archives usually exist on the diocese or archdiocese level.