do you clean and tidy up?
how did you know there are plates under the sofa? you knew they were there an just left them there?
why dont you move the clothes?
you say you get home and do every thing - but what are you actually doing if the house is like that?
i am not defending her at all... but i am messy too and i have lived with someone who believed they didnt have to do anything, and that i should keep house as i was female...they did nothing but gripe about the mess, yet made no effort themselves (they didnt last long)
i do not have dishes under the couch etc but i do have a lot of stuff
in terms of tidying up and managing it...maybe rather than trying to shout it out of her, which you cant do as is clear - try to make it easier for her to manage it...go and buy a proper linen basket - maybe a few of them, carrying one and standing one - and buy shelving, nice looking storage boxes, units, under bed units etc etc...whatever you can think of to control it a bit.
you may not like extra furniture but utilise space such as under the stairs or high up around the hallways etc...
buy a dishwasher...even a small tabletop one
i find storage is the biggest help
if you love her, it would be a shame to give up on her because of this.
(as for the kids, lots of kids are messy, just leave them to it)