I am hoping that you will be able to clarify some compound possessive sentences.
I have been hearing people say things such as:
"She and I's relationship."
"Sally and I's relationship."
I have also heard:
"It is the end of John and your's vacation."
"It is the end of you and John's vacation."
"It is the end of your and John's vacation."
I was happy to help her. Here's what I said:
These choices would be correct though not ideal:
Sally's and my relationship
John's and your vacation
Recasting the sentence to avoid these awkward possessives works best:
the relationship between Sally and me
the end of vacation time for both John and you
I hope that you's and your three-day weekend is fun! (I mean, your weekend!)