Roommate's GF

My roommate during our freshman year of college had a cute GF that he started dating during their junior year of high school. He told me that they had not fucked before getting to college, but they soon did. For three years, they fucked every Friday and Saturday nights and at least on night during the week. I would spent the evenings visiting in other rooms and not enter our room until after 11 pm. By then, they had already fucked and usually were asleep. One morning, I woke up before they did, and I watched as his GF got dressed. I discovered that she had a great body to go along with her great personality.
During our senior year, I started waking up early every morning that she spent the night with my roommate so that I could watch her get dressed. In the spring, they had a big fight because my roommate wanted to open up their relationship so that he could fuck other women. She did not want to do that, but he did. He said that he had a date with another girl for Friday night and he told her that she should have a date with another guy. She told him that she was going to ask me out and he said good, that he didn't mind. She asked me out and after our date, I went back to her dorm room and we kissed but didn't go any further. I went back to my dorm room and my roommate was still there with the other girl. It was obvious that they had fucked.
The next day, I saw her and she asked me if her boyfriend had fucked the other girl. I told her the truth and saw that she had tears in her eyes. I walked her back to her dorm and she wanted me to come up to her room with her. I did, and as soon as we got into the room, she laid down on her bed and asked if I wanted to fuck her. I certainly did and soon we were both excited and naked. I got on top of her and she guided my erect cock into her. Luckily, she came very quickly because I didn't last more than a couple of minutes before I came inside her, the first time that I ever came in a girl. We snuggled for a while and then we fucked again with her sitting on top of me.
We got up in the morning and went to breakfast. While we were eating, my roommate and the other girl came in. They got their food and sat down at the same table as us. My roommate asked her if we had fucked and she said yes, twice. He wanted us to all go back to our room and spend the day in bed. We said okay and soon were all naked in our dorm room. My roommate got in bed with her and I got in bed with the other girl. I fucked the other girl and he fucked her. I didn't really care about fucking the other girl, I mostly watched my roommate fuck her. We continued with our foursome for several months and them I told her that I didn't want her to fuck my roommate any more, that I wanted to be the only guy that fucked her. So shortly before the end of our senior year, we became exclusive and after graduation, we moved in together and lived together for two years before we got married.