Surely petty stuff like that isn't enough reason to end our long term relationship is it? Again, i think it's just an excuse to run off with someone else. I told her i won't be moving out and left it at that.
I don't know you, or the situation but I'm saddened when anyone's relationship takes a turn for the worse. To answer your question, my wife's ex husband was thrown out for the same reason. Didn't help with the (2 year old) child, or the housework, and wasn't the affectionate type. Not saying this is you as well, but I think all of these small things can come together and make a chap look like an oaf, rightly or wrongly.
However, the fact that there might be someone else is a huge factor IMHO. It might be a friend with a lending ear, it might be romantic. What speaks volumes for me is that rather than go off at you for being lazy, that conversation seems to have been skipped and she's gone outside of what's acceptable in a marriage i.e. might be seeing someone else.
Whatever the case, it sounds like her mind is made up. This is your last chance to talk to her properly, ignoring the Facebook stuff and the outside involvement of other people. If after that she still wants out, you don't have much choice. I know how these things go, especially with property, so you do have to think of yourself and fully expect that she will take as much as she can.
My view (without many facts) is that she is seeing someone else, otherwise she would have gone ballistic at the mere suggestion of her playing away. Stand your ground, if she's found someone else then it's up to her to take a financial hit with regards houses, rather than you. Just my 2p