It almost sounds as if you are tracking your changes, and you have your
options set so that deletions are hidden, but your colleague has his options
set differently, so he can see your work. Is that the issue?
If so, there's no easy way around it in MS Word, because those settings
reside on each individual computer. As long as the changes are still in the
document, anybody can see what you deleted if they want to. Your best options
are (a) accept all changes in the document before you send it to your
colleague, or (b) create a PDF of the document. Then your colleague cannot
see what you have deleted.