We grew up together. He’s my full, biological brother, two years older than me. We're two of four siblings; the other two are girls. Our parents are in a healthy marriage. [...] We started out as brothers with benefits. We shared a room. He was naked a lot. He slept in just boxers or naked, and we also shared a bathroom so we'd frequently walk in on each other showering or pissing, etc.
[...] Eventually, when we didn't stop after a few years, we had to talk about it. He slept with a few girls and one other guy, but told me he didn't enjoy it as much as being with me. I hadn't done anything with anyone else. It shifted into something that was sort of... open for sex but did not allow relationships, I guess? I experimented with a few friends, and he would sleep with others, but he didn't get emotionally or romantically involved with them.
[...] We live in an apartment together. What we have now is a more traditional open relationship. We're basically a normal couple, except we still can sleep with other people--though now the other partners are less frequent, and there's a lot of talking about who/when/etc. Sometimes we have threesomes to make it more fun.
[...] One of our sisters knows, and has known since we were teenagers. She was understanding, and told us that she'd once had a crush on one of our Uncles and didn't find our relationship disgusting, and could relate. She asked some questions, particularly to me because I'm younger, to make sure it was safe, but has approved. We haven't told our other sister or parents. We have several friends who know, three or four, and they've kept our relationship a secret and have also been supportive (a few friends are no longer friends because of their reactions). We also are open to certain people we bring home if we're going to do something sexual and want them to know before anything happens, but we normally pick people we think are more open-minded and won't react strongly.
[...] Being sexually curious while young, it is almost impossible to find someone to explore with. You're not supposed to look on the Internet (and may not even know how or where to at that point) and have to look toward people you know. Sometimes your friends aren't at the same place as you, or ready. I always had my older brother as a figure in my life, and as a man to look up to. He was strong, handsome, and available to me. And there's a sense of trust automatically there that you'd have to build with someone new.
It is a safe person to explore with. Now surely there are un-consensual acts that happen as well, but in my case it was 100% consensual, and so it was very enjoyable. Now I do think it will be hard to maintain that relationship, especially if it grows to more then sex. But I still find it worth it.
[...] We try to be very, very careful with who we tell and kind of do small tests to gauge how they feel about less "normal" topics. Taboo subjects. Luckily, a lot of reaction from friends has been positive for us. If negative... what can you say? They're a person you cared about, and you're a person they cared about and none of that just disappears. And to a degree I understand because of how many un-consensual incest relationships go on and how society defines it. It is hard to be angry. Some of them want to only see one of us at a time, or want us to just not be romantic in front of them... some don't want to see us anymore. But nobody has told our family, and that at least is something to be thankful for. They have respected our privacy.
[...] [I would marry him] in a second. Without a doubt.