I doubt very much that they were married. Couples often got together and didn't marry, sometimes because one of them already had spouse (which seems to have been pretty common), or they just didn't get around to it.
My gt grandparents didn't bother marrying until they were in their sixties, just a few years prior to their deaths. There was absolutely no reason why they couldn't have married earlier, they just didn't bother until it was time to make a will.
This is a question that will probably never be answered. I had a look on Ancesty and couldn't find a link for the.