Not specifically Shearwater related, but MacDive allows different user profiles in-app, as well as default having a group based on dive computer. For example, you could dive with a Perdix and a Predator, and each would sync under their own computer, so that if you only dive your Predator, and your wife only dives her Perdix, you would simply click on the icon for that computer and it would only display dives undertaken on that computer.
I like the additional features of MacDive, which is why I don't use Shearwater Desktop for logging, however I would think that different user profiles would be fairly easy to implement in Shearwaters apps, both phone and pc-based.