Luis and I haven't broken up but we gave each other some time to think.
I put "pero" because this seems like new information as much as a substitution, or at least it's a very complex substitution.
BUT, one of your example sentences for "pero" is, roughly, "I can't go out tonight, but I'll go out tomorrow." In one of your earlier replies, you give this example: "Ella no puede venir hoy sino mañana. (substituting)S he can't come today but tomorrow"
I don't understand why these two seemingly interchangeable examples are given first as an example for "pero" in the main text and then as an example for "sino" in the comments.
This seems much more like a substitution, no?
