@DienophileMD
This doesn't come up often enough that there is a rule about it at my school or a specific way it would be handled.
1. you will be a re-applicant. Some schools will look at your application, realize that you could have applied and been admitted to start in 2018 (you took the MCAT in 2017 or earlier, graduated in 2018 or earlier, etc) and wondered why you had not applied, or applied and did get in, during the previous cycle. That could be a question at an interview. How you answer could determine whether you get an offer (in other words, turning down the offer will not have matter) or not. Of course, there is also the chance that you won't get the opportunity to be interviewed because someone will read the application, and think, "this is someone who should have had multiple offers with merit scholarships last year -- if that didn't happen, must be something wrong with him." or "he's too good for us, and he'll throw us over for one of the top schools that will offer merit aid, we shouldn't even bother inviting for interview."
2. Although this is a difficult thing to bring up, what if your relationship is history a year from now? Will you regret having to reapply because you made a decision that, in hindsight, turned out to be foolish?
3. As has been brought up before, what if she is transferred (or let go), before 2023 (your graduation year if you start next year and finish in 4 years)?
4. Is there any chance she can move a year from now and take a job closer to where you will be matriculating in a few months?
5. Will you limit your application solely to schools within 100 miles of Tampa. Do you realize that applying to so few schools is having too few irons in the fire?
Some schools will entertain an application from a transfer after M2 year if there is a good reason. Would you have any intention of marrying her before starting M3 year? That and a super strong record in the first 2 years and on the boards might get you in as a transfer meaning you'd only have to do two years long distance.
To me, there seem to be many good reasons not to let go of an offer this year. Of course, I did 2 years long distance and then got married while the ink on my diploma was still wet. Thirty plus years and still going strong.