The woman, who was adopted as a child, claimed she made the discovery when the pair decided to take DNA tests together to find more about their families – but she has not yet shared the results with her partner
The jaw-dropping story was revealed after the girlfriend shared their experience in a post to Reddit forum “offmychest”.
Posting as u/LetsSinWith the woman claimed: “I just found out that I’ve been dating my biological brother for 6 years.”
She explained: “I am 30 and my brother is 32. I’m just going to call him my boyfriend for the majority of the time while I type this. I feel weird about this. I was adopted as a baby but I didn’t know that I was adopted until I was in high school.
“It didn’t feel betrayed or care much. I love my parents and my parents love me. Who cares if they aren’t my real parents.
“My boyfriend was also adopted and when we met it was one of the things we sort of bonded over. We both didn’t learn we were adopted until high school and we both were lucky and had good families. We weren’t passed around from foster home to foster home.
“Our relationship was and still is great. We understood each other very fast. We were attracted to each other quickly. I’ve never met someone and felt immediate attraction and familiarity.
“Now I know that the comfort and familiarity is because he’s my brother. Not my half-brother. He is my full brother.
“We’ve done everything a couple that has been together for 6 years could do. We’ve said we love each other, we’ve had sex, we’ve celebrated anniversaries, we’ve met each other’s families.
“I’m just glad we both agreed early on that we don’t want to have kids so that has never happened. I don’t want to deal with the health risks and have to raise a child and them know that their parents are siblings.
She continued: “I discovered it when we did the DNA test thing to see our ancestry and what exactly we are. I ordered two for us, we spit in the tube, and sent it out. It took like a month for the results to come back and I was excited to see what we were but before I could even get to that. I saw that we were siblings.
“I was SHOCKED to say the least. I only just found out this information and I haven’t told my boyfriend. I’m really hoping they made a mistake but things are kind of starting to make sense to me now.
“We always get the ‘you guys look so alike’ or ‘he’s the male version of you.’ Long before this test we’ve always gotten compared. We always just laughed it off but I have spent the morning looking at pictures of us together and realizing that we really do look so alike.
“It’s freaking me out and I don’t know what I should do. I still love my boyfriend/brother and we have been together for 6 years. We have a house together and a whole comfortable life. I’m hoping that this test is wrong and will do a real test soon but I’m panicking. I still see him as the love of my life.”
In a later update, she added: “I posted this the other day in but since then I showed him the results and he realized that we’re siblings. He doesn’t want to freak out or make any big decisions until we get a real test somewhere. But I can tell he is freaked out and it was odd laying in bed next to him.”
The post has since gone viral and has been shared to numerous platforms, including @twohottakes, the TikTok account for a podcast which sees the hosts react to Reddit posts.
Responding to a video about the post, which has racked up over 14 million views, commenters shared their sympathy for the couple.
One person wrote: ” That would probably be devastating.”
Another agreed: “That’s a really sad situation. Imagine how hard that would be to digest.”