My husband and I are dating another woman, but I'm feeling left out

I am new to the poly life and I am trying to get adjusted but it isn't working. My husband and I are dating his ex-wife, we both love her but I feel as though I am being left out. He calls me to talk to her instead of calling her, when we share a bed I always end up sleeping it the guest bed or on the couch, and I feel as if he doesn't want or need me anymore because he has her again. I love them both but I don't know how to talk to them about what I am feeling without hurting them or losing them

What you've laid out here is a really good start for knowing how to talk to them. Sit down with your husband and let him know that parts of this arrangement aren't working for you right now. Tell him specifically that you don't like when he calls you to get through to her, or when you end up feeling unwelcome in the shared bed. There may be some simple fixes here, like him not treating you as a go-between, you two setting aside date nights or private time for the two of you, and a better way to manage bed-sharing that ensures everyone is included.

Keep in mind that not all "messages received" are "messages sent" - it may not be true that he doesn't want or need you anymore. He may just be experiencing NRE, or he may think that you prefer sleeping on your own, or he may just not have thought through his behaviors and how they're impacting you. So make sure not to bring this up in an accusatory way - more informational, just "hey, FYI, this bothers me - can we come up with a way to resolve it?"