I don't have an answer but I do have an idea. As long as the electonics/phones are not replacing your relationship needs or communication with each other, I would say it might just be that the two of you are just tired from a long day of work. This doesn't mean that a deeper problem doesn't exist; this just doesn't seem that odd to me especially when I know of professional ballet dancers in relationships that are so worn out at the end of the day, they aren't even interested in their cellphones, much less each other. (Not necessarily a good thing for healthy relationships, but not really bad either.)
However, if you find that the two of you are beginning to drift further and further apart each day, then there might be something more serious going on.