EFT training that I had assumes that there are no third parties in the relationship. Therefore, I only work with couples where there is no ongoing infidelity and non-monogamy. If you or your partner have a romantic or sexual attachment with third parties, then either you stop it to work with me, or turn to couples therapy with other professionals who were trained in it.
I do work with infidelity injury and restoring connection after cheating, but when it is already in the past.