So my mom just e-mailed me saying the first rsvp's came in! So exciting! So I thought I researched all of the etiquette stuff, but for a family member on Fi's side has a widowed aunt. I sent the invitation to her addressed as Ms. She rsvp'd with Mrs.!!! Oh no! I am so embarassed. I thought once you wre widowed you went back to a Ms. I guess not!!!