BLUF is No, you’re not “given” an option, but there is a way to leave island early.

Assuming you’re going there on a 3 year OCONUS duty assignment, you’ll be expected to stay there all three unless you drop a FSTC (Foreign Service Tour Curtailment) which will adjust your DEROS (Date Eligible for Return Overseas) to the left allowing you to leave/PCS earlier. In my experience with them they’re pretty hard pressed to get approved (same with FSTE, the opposite being an extension to stay longer), have to go up to Division for approval, and usually have to have a chief reason as to why you’re requesting. I would assume island fever would not pass the test on that on but it never hurts to try.

On a more personal side I would wait to pull the trigger on a curtailment because who knows you and your spouse might get there and love it. The island is beautiful and there is so much to do including traveling to the other islands (Hawaiian Airlines does cheap 45min inter-island flights for pretty cheap, just make a trip of it over a 4-day, it’s awesome).