I'm going to second GutOnc's advice.
You're not going to get a match waiver, based upon anything you've mentioned. In order to get a waiver of your match, you'd need to prove that some new event / issue has changed things such that you can't start. Changing your mind from IM to EM doesn't work -- ROL's were due Feb 20, I doubt anyone will believe you changed your mind in the last 3 weeks. Not matching with your partner isn't a reason either -- either you "couples matched with linked rank lists" and you could have chosen to both not match rather than just one of you matching, or you "matched separately as a couple" and you could have couple's matched. Either way, not a reason for a waiver. And, since your SO didn't match, they can simply come live wherever you are.
Matching into a new field as a PGY-1 is not easy. First, you'll have to tell your new PD within the first 1-2 months that you're thinking of leaving. Second, how exactly do you think you're going to get the time to interview? Internship is busy, and doesn't tend to be very flexible. Third, you'll need letters from your internship, and after you've worked with me for 1-2 months your letters are likely to say "Well, like any intern in the first 1-2 months, it's hard to say. So far, so good". Next, there are funding issues with changing programs (there are other threads about this). Last, Match Day is mid March. The ACGME requires that we give residents 120 days of notice if we're not going to renew them, and many programs require the same of their residents. That's March 1. So, you might be stuck not signing the next year's contract before the match results come out.
So I think you need to think about how badly you really want EM over IM. As mentioned above, changing to your home program's EM program is often the easiest -- easy to interview there, easier to impress, etc. It's not impossible to transfer as a PGY-1, you should consider asking for vacation in late November or eearly December for interviews (or late January).
Another thing to think about is what your husband wants. From your post, I assume he was looking for IM also. If so, if you're doing well in your program, that will be a HUGE incentive for them to take him next year. If they don't and he matches to another location / city, there's a reasonable chance that you would look to transfer to be with him. If they don't want to lose you, they will want to take him. This would set him ahead of the other IMG's with good scores.