Ending a sentence with a preposition is considered a kind of word crime.  In matters of style, ending a sentence with a preposition tends to make the sentence look and sound awkward. For example:
“I am not writing a play I can’t star in.”
Might read better as:
“I am not writing a play in which I cannot star.”
In in this case is the preposition.  The general rule is that when writing or speaking, one should avoid ending a sentence with a preposition.  Correct grammar, say some grammarians, has it that a preposition should always be placed before a noun or a pronoun

However, if you are not able to replace the preposition at the end of the sentence without it sounding unnatural, you must certainly stay with that structure.

Ending a sentence with a preposition – it’s all about style.

“There is only one thing in the world worse than being talked about, and that is not being talked about.” – Oscar Wilde
This flows as a sentence and the preposition fits at the end of the sentence. If it doesn’t jar when you say it or read with the ending of a sentence with a preposition, there is nothing stopping you from using it.

If it does sound awkward, as it does in many instances, you can restructure the sentence to lose the preposition at the end, and it sounds quite correct.
“She is the worst customer I have ever had to cope with.”
“She is the worst customer with whom I have ever had to cope.”

With is the preposition here.  Both of these sentences are correct.  It is a matter of what sounds right to you, or better.  There really are no strict rules.  It could be argued that grammarians would say the first sentence – with the preposition at the end, but the second sentence, which observes the style rule about not ending a sentence with a preposition, somehow reads better when it is written down.  The reasoning is purely a matter of taste. The second sentence sounds very awkward when it is spoken.

The general rule is that when writing or speaking, one should avoid ending a sentence with a preposition.  Correct grammar, say some grammarians, has it that a preposition should always be placed before a noun or a pronoun