In a committed relationship with my partner I moved in with her. Several weeks after moving in I went to an evening work dinner. I needed a cab, but a coworker offered to take me home. He put his hand on my thigh, I asked him to let me out, he touched my face and kept driving. At our apartment he walked to the door with me. I thanked him, but he kissed me and took my key and opened the door. Sex was on the couch, he left me with a kiss on the mouth. I didn't tell my partner, now I am pregnant. When she finds out I let a man in and he had sex with me on the couch she will leave me. I betrayed her, I don't know what came over me.