Dunno if this is a Murican thing, but just because someone doesn't feel like working 24/7 doesn't mean they are lazy. Work isn't and shouldn't be everything. Mental well being and feeling good with yourself matters more.

As for her falling out of shape, that will sometimes happen. If you conclude that you no longer find her attractive in any way better just leave now. There's no information as to how long you two have been together so it's not clear whether this is a long established relationship that should be fought for, or something that should be quickly cut off due to incompatibility.