From then on in.

[pinosilano]

Hola,

Context:

She told me she didn't want our relationship to start on a physical basis as that is how it would be principally defined from then on in.

¿Se puede traducir así?

Ella me dijo que no quería que nuestra relación se iniciara sobre una base física, ya que así se definiría principalmente a partir de entonces.

Si es así no lo entiendo mucho.

Muchas gracias.

[Perikles]

I think the English is really bad, or just wrong, or American. It means that the relationship would be defined "in that manner", or "the physical basis would set the tone of the relationship" or as you suggest "from then onwards".

Edit: I notice that my "onwards" is flagged as a spelling error, which is ridiculous. Perhaps some dialect (or American) has "on in" as an alternative to "onwards"

[Rusty]

None of it is American English.

We would say, "from then on out," which means the same as "from then onward."
(We use either onward or onwards, even though spellchecker complains.)

[pinosilano]

Es una frase de un diálogo entre dos escoceses.