What about: yourself? The person you are? Why wouldn't that be enough? I really don't get your main problem, I suppose. Even in a mono world, someone who is dating you/wants to be in a relationship with you for the 'extras' you have in your life solely ... is that what you have been looking for? I don't think that I am wrong when I guess that there was more special about you than a 'mono trump card' you don't have any more.
And btw: Don't regard your wife as 'baggage' just because your family life and your relationship with her takes up some of your time. Aren't you a happy and fulfilled human being because of this? That's plenty to offer to any new person coming into your life, from my point of view.
Facts: 30, female, bi, v-type relationship with Sward (husband, straight, mono) and Lin (boyfriend, straight, mono), poly-fi and co-primary.