Where do you live? I understand your fear that you might narrow your skill set, however, I have mostly found that NICU skills are not narrowed as much as they are miniaturized, lol. It's still an ICU. It is true that you MAY pigeon-hole yourself just a little, however, with at least two years experience, I think you will find quite a few openings (especially travel nursing options) across the country. Maybe tell your bf not to move for the next two years, lol? Is he military? Also, not that I've tried recently, but I do feel that I could at least get some interviews for more medsurg like floors.
Also, if you really love NICU, think of it this way. NICU nursing is an extremely specialized skill - an extremeley specialized skill they need almost everywhere in the country. I have had friends leave after only one year of experience and find other NICU positions relatively easily in other parts of the country (even in California). Moreover, while this may not be best practice, many NICU's will hire new grads over experienced adult/medsurg nurses. This is one of the many reasons that helped me decide between accepting a medsurg offer vs. a NICU offer (you can look back at my very first posts). I just decided, well, I could either start off in NICU (my dream job) or die tomorrow working medsurg and never even get to NICU. A little dramatic, I know, but it helped me decide. Btw, I have nothing but the most profound respect for medsurg nursing...I just wanted NICU.