I was writing a letter and got confused with this line.
I am thankful for the opportunities that have been provided me during my tenure.
or should it be
I am thankful for the opportunities that have been provided to me during my tenure.
I was writing a letter and got confused with this line.
I am thankful for the opportunities that have been provided me during my tenure.
or should it be
I am thankful for the opportunities that have been provided to me during my tenure.
"Provided to me" is grammatically correct, but "provided me" is a common, older, narrative style. You'll find other examples where "to" is missing but implicit, such as "Elizabeth, it has been so long since you have written me that I was quite sure you had forgotten me!"
If you are writing the letter then I would include the "to"; omitting it might appear inappropriately stylized, maybe even pompous.