No, I don't think it is a bad career move. Unless you are interested in GI or Cards, most fellowships will still be achievable for you anyway. ID, Endocrine, Rheum, all are not that competitive. If you were interested in some hot-shot academic career that would be a reason not to go as well. Hospitalist is even less likely to care. In fact, since you will ultimately need to live near your fiance anyway, you may be able to make better connections to get a job in her area at the community program in her area.
What would be a bad move? Spending a significant amount of time away from your spouse when it probably won't matter.