I find myself really fascinated with this thread and its meaty topic!
I am trying something really new for me. I am attempting not to get attached to knowing the 'outcome' of a relationship, whether casual or more involved.
Before, I would have an idea of what a relationship could develop into. I was one of those folks who did not have casual relationships - not because I was consciously avoiding them - but because I got involved in a very serious, intended to be lifelong, partnership with Beaker. As I was monogamous, I never considered another serious partnership alongside that relationship. And since I was monogamous, I did not think about more casual involvements, like a friends with benefits setup. In fact, I did not even meet anybody during those 12 years who, looking back, could have been a FWB as I literally could not imagine that.
So, now that I'm ethically non-monogamous, I can imagine primaries and secondaries and casual and FWBs and all sorts of constellations. I'm seeing Whip, and theoretically still seeing Oil Man. (That is/has fizzled, which is ok.) I did not consider that I could develop feelings for a casual partner and that is what happened with SW. That did not turn out how I had hoped - he is not interested in a more serious connection with me.
But the experience has informed my thinking about future relationships. For instance, I am skeptical that anything long term can develop between Whip and I. He's much younger than me and, more importantly, in a different stage of life. That can make a great deal of difference. However, I am thoroughly enjoying myself, consider him a FWB. So that is a casual connection. I've learned from being with SW that one never knows. So I'm winging it and seeing where, and if, things go. I am very unused to giving up this level of control, of 'knowing the future' would look like for us. (Caveats! Of course, one never truly knows the future.)
And I also learned that, of course, I get attached to my FWBs. I care about them, want them to be happy and do well in what they want to do. I take care to accept the consequences, good, bad, and indifferent, of making that attachment. I struggle with this. And I struggle in trying not to see the future, to not imagine what could be, but try and accept and live in what is.