The proper way to address a letter to a married couple with a suffix at the end of the name is to adopt the traditional rule of keeping the man's first and last name together.
Mary and John Smith
This is the proper way to address a married couple when using this format. So it follows that:
Mary and John Smith Jr.
Mary and John Smith III
Mary and John Smith, Esq.
would also be the proper outline.
The two letter suffix used to designate a Spain internet address is es.
de....
a web address suffix.
no, 's' would not be a suffix.
Addressee
A suffix for the word "marry" could be "-ed" to form "married."
"E" is not a word. E is a letter, and a letter cannot have a root, suffix, prefix, etc.
suffix
the second suffix is ususally a single letter
If a site has the suffix .edu then it is most likely is an education website.
Australia.
WWW is an identifier, it is the HTTP suffix, and the address prefix.