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My Fiancé of 2.5 Years Just Told Me He Had Sex with His Sister

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So my boyfriend (21) and I (22) have been together for 2 and half years. Yesterday we got super drunk and he began to cry and admitted he and his sister (they’re a year apart) lost their virginity to each other. When I tried to ask him details he said he “couldn’t remember” or swore he personally didn’t do anything but have intercourse with her. I had met up with his sister (20) to talk to her about it and she was able to tell me vivid stories about their sexual encounters as if it happened yesterday telling me it started when he was 6 and she was 5. It didn’t start off as actual sex at first but then it started to get intimate after a few weeks. It (supposedly) stopped when he was 12 and she was 10 but I’m having trouble believing them both. Just from how super close they were (“driving” around at 3 am together), the way they’d jump when I’d come in the room or whisper as soon as I left the room and get extra quiet when I’d approach them. I’m trying to figure out a way where I can tell if it lasted till I moved in with him. Before we actually got together there was an instance where he (19 at the time) and her (17) was sharing the SAME bed and that’s when my intuition kicked in and I said something about it and he made it like I was crazy (though my feelings were right due to what they did in the past). I just don’t know anymore and I’m messing up my head thinking and trying to understand it all. I can’t even talk to him about it without him getting defensive or bent out of shape. I want to stay with him because I love him. But I don’t know if he’s being fully honest with me, I don’t want to marry a liar. He said he told me because he loves me and wants a future with me. It’s just that what he told me is a hard pill to swallow. I need advice on what I should do in this situation, so any help is help. Thank you and God bless. (From the USA)

My Fiancé of 2.5 Years Just Told Me He Had Sex with His Sister

Answered by on -


Incest is a powerful dynamic that leave lasting scars and many residual feelings. The revelation and story behind it is disturbing for a variety of reasons. First is the chronic nature of the situation. This isn’t an event that happened, but rather an ongoing situation that took place over a period of years. This means that the home they grew up in was most likely poorly monitored — with parents who were negligent of their children’s safety. This, too, has a tremendous impact on their psyches as the situation evolved.

The fact that your fiancé feels bad and that he carries around the guilt and turmoil that comes with this will certainly affect your relationship. I do not think this issue is something the two of you should try to manage on your own. A professional therapist with some experience with incest would be helpful. You can find someone from the find help tab at the top of this page or this group who may be able to guide you.

Finally, your fiancé’s statement that he: “didn’t do anything but have intercourse with her…” is very telling. It is an attempt to minimize the impact of what this is.

As your plan was to marry into this family, I highly recommend couple’s counseling with someone from the above-mentioned resources to unravel your feelings, his issues, and the secrecy that has surrounded all of this.

Wishing you patience and peace,
Dr. Dan
Proof Positive Blog @ PsychCentral

My Fiancé of 2.5 Years Just Told Me He Had Sex with His Sister

Therapists live, online right now, from BetterHelp:

Daniel J. Tomasulo, PhD, TEP, MFA, MAPP

Dan Tomasulo Ph.D., TEP, MFA, MAPP teaches Positive Psychology in the graduate program of Counseling and Clinical Psychology at Columbia University, Teachers College and works with Martin Seligman, the Father of Positive Psychology in the Masters of Applied Positive Psychology (MAPP) program at the University of Pennsylvania. He is Director of the New York Certification in Positive Psychology for the Open Center in New York City and on faculty at New Jersey City University. Sharecare has honored him as one of the top 10 online influencers on the topic of depression. For more information go to: He also writes for Psych Central's Ask the Therapist column and the Proof Positive blog.

APA Reference
Tomasulo, D. (2020). My Fiancé of 2.5 Years Just Told Me He Had Sex with His Sister. Psych Central. Retrieved on November 24, 2020, from
Scientifically Reviewed
Last updated: 28 Apr 2020 (Originally: 30 Apr 2020)
Last reviewed: By a member of our scientific advisory board on 28 Apr 2020
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