A good point. I envision them kind of walking out of a tunnel into the light, which is why she's bright and his top/back half is in shadow. Maybe I will try doing a background... but if I have little experience in figure-drawing, I have infinitely less in scenery, so this may prove an insurmountable feat... haha.
I do live drawing classes, and have found putting in scenery is essential for even that- posey pics are ok without it, but otherwise, the lack of location gives them a disjointed look that looks like they're not meant to be there. The background will also distract from any incorrect shading anyways The glory of location ^^