My FI's aunt is a widow who has started dating again and is being invited with her long-time boyfriend. I know the proper form for widows is usually as Mrs. (either with the deceased husband's firstname/lastname, or her first name, his last name, depending on her preference). But since she's dating again and we're inviting her boyfriend along with her, it feels really weird to address the envelope to Mrs. FI's Aunt and Mr. New Boyfriend. Does she go back to "Ms." under these circumstances?
Re: Addressing Invitation to Widow
my mom gets really offended by "ms". after nearly 12 years of widow-hood, she still goes by mrs. john doe
If it were me I would address it Ms (first name) (last name) & Mr. (boyfirends firstname) (boyfriends lastname). If you are truly concerned that Ms will cause offence you could just do (aunts first name ) (aunts last name) & (boyfirends firstname) (boyfriends lastname) and leave it out entirely. She probably wouldn't even notice.
ETA: I would actually advice against asking her what she'd prefer. If I were widowed and I have finally started dating and then someone called me up and asked me if I still wanted to be MRS and have my boyfriend listed I would think they were judging me for dating. Even though that is the farthest thing from your mind that is how I would feel. I would feel guilty that i was dating someone that wasn't my former husband. Side note if I recieved an invite that used MRS and had my bf's name on it it would invoke similar feelings of guilt and judgment. just my 2 cents.