Originally Posted by MeeraReed
One more thought: if you do start seeing a therapist, and after a few sessions you feel that they are not very poly-friendly or are not giving very poly-friendly advice, don't be afraid to seek out a different therapist.
I wouldn't wait for a few sessions, I would find out before laying down a single dollar. You're within your rights to interview potential therapists before hiring them. If they refuse to interview, walk away. And during the interview, ask them specifically if they are polyamory-friendly. Use the word "polyamory." Whether they know the word will be the first test. Their reaction will be the second test. And a direct question whether they support it will be the final question.
Also, ask them about their general therapy process. For example, mine told me that she does not do long term therapy. She prefers to help people when they're going through a rough patch, and she provides coaching via phone afterwards, but she doesn't see people who need long term care.