Well that last page, looks like Chiho is fully aware of their dynamic... You could say they suit each other but it feels weird, like there's no romance, just comfort.
Oh she got a job and she's a genius, now? alright xD
"When I thought we would be living together, I figured I shouldn't leave you to do everything"
I'm sorry, but it's to my understanding that you've been living together for quite some time... I think she meant living as a couple in this context but then the "Eh?" at the end wouldn't work properly