I have been with my girlfriend for 8 years. We are both 23 now and recently my sexual urges have become unbearable for me to suppress and her to fulfill.

She suggested me finding another sexual partner. I did and at first it was going great but I started to catch feelings for him as well as he caught feelings for me. Through all of us hanging out and me wanted everyone to get along and be comfortable with everything my girlfriend caught feelings for him too. As well as he caught feelings for her.

We agreed in all fairness that there is no primary relationship. It is somewhat of a triangle. Him and I, her and I, and him and her. Sometimes we all do things together but I can't get past my feelings when it is just them alone.

The jealousy is killing me. I know it's wrong but my brain keeps telling me that them being together is wrong. I can't get past this feeling.

Tonight is the first night since this all started that they will be alone together. They are planning on having sex. My emotions are so controlling that I have to leave the house. I can't be there when they are alone together.

Even through all their reassurance I feel hurt, abandoned, and utterly jealous. I dont want them to be together. Any advice?