Before I moved to the city I live in now I felt like I never really knew who "me" was. I met my husband when I was 16. I fell into his group of friends, mostly by default and just became a part of that world.
It took a drastic move to a new city while starting a family for me to find myself and to discover my independence. I've found friends of my own here who I'm friends with on my terms rather than just because they are friends of my husband. I also joined a sport that makes me feel like I'm a part of something and strong and powerful and sexy.
Also my husband's job takes him away for long periods. I've learned that when there is a crisis that I can deal with it (and I can deal with it all on my own). I think that being independent makes me more interesting. If you are always with a partner what do you have to talk about with them?
Another step in my independence when it comes to poly was realizing that I only wanted to be with people who want to be with me. I don't need to be a part of a "we" to be ok with myself. That was a huge revelation for me. It made me much less fearful about what the future held for my husband and I. If one day, by chance, he meets and falls in love with someone he wants to be with without still being with me I know that I can get through it and that my husband and I will be able to redefine our relationship as friends and co-parents. (I'm not saying it wouldn't hurt, but I would manage).
I don't suggest radically changing your life and moving to a new place but it was exactly the kick I needed to find my independence.
Everything will be ok in the end. If it's not ok it's not the end.