I found your post interesting, thoughtful, and well-written (at a time when I've noticed a surge in silly and shallow posts on this forum). So I'm not sure why you're being called "shallow." I totally get what you're saying.
However, until I got to the end of your post I assumed you were in your 50s/60s...are you telling me you're only in your 30s???? All this talk about aging and ending up alone...really???
I understand what you mean about the feeling that you grabbed for multiple bones and ended up with none. This happened to me in 2010, when I was 29. I lost my three long-term lovers all at once in the space of two weeks. Two because they chose monogamy with someone else. I turned 30 feeling like I had lost everything, and wondering why I hadn't been smart enough to do what my monogamous friends had done--settle down with their college boyfriends.
Well, I hadn't done that because I didn't want to. I wanted to explore and date more and make more connections--and I still do.
Dating in my 30s is definitely different. But I find it's better--I am clearer about who I am and what I want, and so are the men I meet. Yes, I'm sure it will get harder as I age, because dating/seeking partners does have an element of shallowness/appearances/attractiveness in it. But people find love later in life all the time. (And "later in life" still seems a long way off to me).
Some of the previous comments on this thread bother me. I don't think it's fair to blame "certain types of poly" or to say that you are not doing love-based dating and that's what your problem is. It sounds like you had loving relationships that you expected would grow more serious, but instead you remained secondary and were eventually dropped.
I am practicing solo poly. I am not seeking a primary partner. My ideal is to date men who are also solo poly. But I do fear that I will end up secondary to two or three people and primary to no one. It's sort of paradoxical.
Anyway, I am in a non-monogamous relationship that is fun and caring and happy and totally right for me. I don't give in to those fears.
Single, straight, female, solo, non-monogamous.