I suggest simply remaining aware of feelings and thoughts and being honest at all times. Awareness and honesty are the things that seperate a true poly relationship from a cheating and deceptive one.
Also, remember that love is the goal here. We choose to be in relationship with one another so that we can experience love by giving and recieving love. A pure type of love can flow through us if we are honest and focused on honoring one another. Patience with one another is important.
Best wishes to you !!