Well, even though we have lived together for 20 years, and have half-raised a family, we haven't married, so I haven't had to even think of that issue.
However, I've noticed that several of the older quilters I know put Mrs. so-and-so (full married name) on their labels, so it's clear it is their married name on the lable.
How about using "nee" on the label? I have to do a lot of record searching in archives and places for my day job...in my requests I always put a maiden name as "Jane Ann Smith nee Johnson" so that who ever is getting my requests knows has all the information.
I hope that helps.