lunakat said: I think there was a chance it could have been Cutter's.
Not Cutter's at any rate. Three years later puts her encounter with him one year too late.
My explanation has always been that she "stuck with" him until she was reasonably certain and then started sharing with other Go-Backs deliberately to sew doubt about the paternity.
And Rayek's comment about "Not even Timmain can open your soul" is probably really Timmain not even bothering, out of respect for Kahvi's wishes, and Rayek putting the wrong interpretation on "I cannot."