I attended the wedding of my significant other's sister this summer. His sister and his ex-wife have remained friends since their divorce over 5 years ago. My significant others ex-wife was a member of the bridal party.
He and I are not married yet. However, we have been together for 5 years. I consider myself a member of his family and vice versa.
Her name was listed in the wedding program as MRS. First name and their shared last name.
Will you please let me know if the ex-wifes name was printed correctly or appropriately? I personally didn't think it was appropriate but, I was also being personal about it. I'm not saying "it's all about me." I just wanted know on account that it rubbed us the wrong way.

Thanks
AB

I don't believe that is correct. Even if she continues to use his last name legally, she is not married so it should be Ms. Last Name