Polyamorous relationships are possible in some cases, but can be very challenging for most of the people. Because they can trigger many uncounscious fears and weaknesses. As just happened to you. It is painful at the beginning, but you can convert this experience into wisdom. Face and observe all these negative feelings. Why are they here, what are they trying to tell you about yourself. It is not easy, but worth doing. I wish you feeling well soon and have power to overcome these obstacles. Time will heal you.