Tanya Lamden, Sherloque and others in “Unfinished Business”

I don't love Shay. We're friends.

Sherloque

All right. Well, let's take a look at that, too, shall we, hmm? So this is a friend from another Earth, for whom you left a high-paying job, and for whom you have dedicated every waking moment of your life trying to help. It doesn't quite add up.

I can't love Shay. He's my dead husband's doppelgänger from Earth-2. How crazy would I have to be to fall in love with him?

Sherloque

No crazier than marrying the same woman from five different Earths. [off Tanya's look] Oh, I know. Very good at marrying people, but not so great at staying married. Along the way, though, on these countless Earths and countless doppelgängers, I learned there is one thing that makes all of us unique. And if that... is what you fell in love with, well, then,... perhaps a face doesn't matter that much.