If you have friends that you find attractive - that is one option. They may not be interested or find you both attractive in turn but you do start with a measure of trust in an already existing friend relationship.
Some poly communities - like mine - do list swing events on our meetup listings. Others separate out swinging (or kink events etc.) very strictly from poly.
If you google search for swinging sites, you can quickly find some options for online listings. There are also swing clubs that may be an option for you. You can google that too fairly easily.
Out of curiosity, what would you and your do if a potential is attracted to one of you but not the other? Say thanks but no thanks?