Implicit commitment

Is it insensitive to say to your partner that you don't consider the relationship to be a "forever" thing?

I mean marriage is the only occasion when this promise is explicitly made. But I guess what I'm trying to get at here is how common this assumption of forever is with people, even in the very earliest stages of coupling. I've felt it multiple times in my life-- I could never help it. And my heart broke the time when I realised that my best friend and partner of five years felt it, and I didn't.

Relationships are pretty much defined by the amount of yourself that you are willing to share; with the remainder of the "person" you're seen as being made up of unconscious assumptions and extrapolations based on what will be by definition that person's most impressive side.

lol I just made a typo at the end of that last paragraph. Instead of side I typed "size". Then I giggled because it was totally a Freudian slip.

I guess the reason I'm typing all of this is because I'm finding myself having to answer these questions as I consider how to approach a co-worker at my new job with whom there is a mutual attraction.

I find myself resisting the idea of a committed relationship, because I know that's not a promise I can make in good conscience. But I really miss having a intimate friend, and sex has been in my experience the easiest path to forming an intimate relationship.

And also I really would like to have sex with her.

What I worry is that she might consider sex to be something requiring a committed relationship; and that I will agree to it just because I want to have sex. And that would be wrong.

So I find myself pondering just how committed to the relationship I would have to be in order to not implicitly promise anything I'm not capable of following through on.