Know how they always say the word is really small? Well I can tell you first hand that it's very small.
When I was in college I met a girl who I became great friends with. We never technically dated, but we did have sex many times. After college she moved back home to California and I got a job in Chicago. We tried to stay in touch, but this was back in the 90's, so not like today. I got a job at a small company in the outlying area and settled into my new apartment. About a year later I met a woman by chance and we quickly became friends. A month later we were officially dating. She had the same last name as my great friend from college, but I didn't really think about it because she said she was from Ohio. By years end I proposed to her and we set a wedding date for the spring. My fiance was working all the plans, creating the venue, and inviting all the people. I was work a LOT of overtime to pay for the wedding so I really didn't pay much attention to who, what, where, and when. My job was to pay for it and show up. The week of our weeding saw many people from out of town showing up. It was so hectic I didn't know if I was coming or going. My finances mother, father, and sister where scheduled to arrive the night before just in time for the rehearsal dinner. I remember showing up to the church earlier and as I walked around the corner I ran into my great friend from college. I was so surprised to she her there and immediately wondered how she got invited. I know more than asked her how she knew I was getting married, and she ask shocking.... "YOU are marrying my sister"?
I immediately pulled her into a nearby closet and asked her what the hell. We had no idea that I had been dating her sister for a year. Evidently they used to live in Ohio and moved to California the year before she and I went to college. My friend says she's from California because her parents still live there and now so do she. My girlfriend says she's from Ohio because she left for college before her parents moved to California and she's never moved to California with them. So to her Ohio is home. The subject of who her sister is never came up and although we talked about her parents, my friend from college and I never did talk about her parents or family. So I married the sister of my college fuck buddy. We decided to tell my fiance that night because I didn't want her to find out later and want a divorce. It was kind of emotional, but my fiance admitted that it was before we met, and there was no way I could have known. So we went ahead with the marriage. Good thing too, because we're still married and have 3 kids. Just kind of forgotten about the whole fuck buddy think with her sister while we were in college.