Not sure if anyone else needed to know this...but after FMIL looked at my 100 already printed & glued invites and said it shouldn't say 'Mrs' before her name because she is divorced (but still using her married name!)...Bill Gates has backed me up! haha...thought it may help some of you as well!
I found this on MicroSoft's website under proper writing of a business letter..
'In addressing a woman, it's useful to refer to previous correspondence from the individual to see whether she included a courtesy title when she typed or signed her name. If you have no previous correspondence, use these general guidelines:
Miss is used for an unmarried woman.
Mrs., with her husband's full name (if known), is used for a married woman or a widow; if a divorcée retains her married name, use Mrs. plus her own name, not her husband's.
Ms. is used in any of the above cases if the woman prefers it; it's also used if you do not know the woman's marital status or if you're addressing a divorcée who has resumed her maiden name.'