Is having my essays proofread inappropriate?
The only correct answer is to ask your instructor.

As a general rule though, proofreading is encouraged. In the professional world, proofreading (or copy editing) is a normal part of scholarship because the goal is to make the final paper as neat and polished as possible.

Sometimes it is appropriate to cite help you have had with a paper. If there is legitimate contribution and collaboration, this is often done with giving co-authorship. If a specific idea is used, this is often in the form of a footnote. For proofreading, this is sometimes in the form of an acknowledgement; sometimes proofreaders are not recognized at all.

Unless your instructor specifically prohibited proofreading, this is not cheating/plagiarism.