But instead it'd be Msr. Jones. Msr meaning 'a man is married'. It is the male equivalent to Mrs.
Example being, George Bush and Bill Clinton - they can use the Msr. abbreviation. Thus former US presidents can be addressed as Msr. Bush and Msr. Clinton, since they are married, in addition to the long established Mr. Bush and Mr. Clinton.
In this case you can think of Msr. As meaning "Monsenior" which is now an English hijack word, in order to balance "Mrs. with Msr."