She doesn't think she was, hence the we. She wasn't blaming him, or herself, or anything really other than circumstance.

But here they were at the end of the universe, and apparently they were going to talk about them. Finally.

She nods.

"I think we should. I think that's the point, sort of - we're at the end of the universe. The end of everything. Like a last chance, and we've just been ignoring it. Pretending it's something other than what it is."