Without knowing your exact situation it is hard to know what you could use for thought material, but I will therefore extrapolate somewhat from my own experience. I needed to know that I remained relevant to my sig other despite his interest in some variety. He and I are the best of friends, and I feel pretty confident at this point that he would not easily find some one else suited to him emotionally, though there are some things he wants to try fun and games wise that he doesn't "want to do with some one he loves". In reality, we all share each and every one of our loved ones with other people in one way or another - whether that loved one is our intimate partner shared with some other intimate partner, or is our best friend that we have to share with some other close friend of theirs, or whether the loved one is a parent that is shared with our sibs and other relatives etc. The bottom line of poly is that poly people deal honestly with their reactions to this inevitable sharing, and don't sneak around in their romantic attachments (or at least ideally they don't), and in a good poly relationship the various partners in the relationship are all made to feel valued and special, even though they recognize they are sharing.