I feel like sometimes on mumsnet people say this as if it's the easiest thing in the world forget the emotional side of it including co dependendence, abusive behaviour or "love".
The practicalities are the hard bit, especially when you have children, even more if you have children with additional needs even more if you have no family of your own to support you, if I were to "LTB" I would be homeless, not just me but my kids too, benefits take ages to come through and the rental market is a non existent, crippling expensive shambles.
AIBU to think there are lots of couple living together who cannot separate due to financial and practical reasons....
Or am I kidding myself and other people do it