How should one show possession in "and I" constructions?

Question

I share an office with a co-worker and wanted to write something about the office that she and I share. Should I do something like one of these:

• Stacey's and I's office
• Stacey and I's office

?

Answer 1

As I is the subject personal pronoun, it is best used when Stacey and you are the subject of the verb.

• Stacey and I share this office.

As Stacey's in your example has a possessive meaning, a possessive pronoun makes most sense here.

• Stacey's and my office

Having said that,

• the office Stacey and I share

(only slightly modified from your question) is probably easier for most listeners or readers to parse.