Is it odd that I either agree or disagree with both of you? I enter relationships making neither assumption.

I expect the relationship will last as long as it wants to, which could well be forever (and that, given the previous, would be preferable), but knowing full well there are many reasons it might end.

(I actually have entered into relationships I expected to be short-term, but that was where an imminent long-term separation was expected, and is a special case.)