I was unusure of whether or not to be open about the way some of my alters and I feel/felt towards each other. It's very hard to explain so that someone else understands and accepts it. In fact, it is hard for me to understand too, because although I understand and sense the relationship and the feelings, I don't have consciousness of very much of our relationship. It is my guess that the details of our history together (on the inside) are withheld from my awareness most of the time.
Anyway, the first time I consciously interacted with an alter ("D"), he identified himself as my "twin brother", and I knew obviously that he was not my biological brother and that we did not have the same parents, or could call the same parents our own together. But our relationship could only be described as a sibling because of how close we were, as alters together. Anyway, he was very, very affectionate towards me and was always during all of our interactions. He said he loved me very much, romantically and in every way, and always showed it. It never felt weird to me, only new to my conscious awareness; for some reason I just intuited that it was something I was already okay with and already understood (I wondered - just like I forget my dreams, which are inner experiences, I might be unable to access memories of inner interactions with my alters). The main thing I watch out for is manipulation, abuse, ignored discomfort, etc - of which there wasn't any that I felt yet. So if he was being kind and listening and wondering if I was all right with how he was behaving, I found no reason to be put off by him. Because beyond the extra "romantic frill", we were still just a pair of buds and joked around a lot like two brothers would otherwise.
And this kind of "no-boundaries" affection/relating style appeared again in my system a few times. It seems like it might be a running theme that amongst some of my alters, monogamy is not the norm. And it makes sense because they don't live on the outside and so don't have to be subjected to societal norms, nor have to deal with any prejudice or etc BS from other people who might not agree with what they're doing. They kind of live in a lawless inside world like the Lost Boys or something, so I think it's all to be expected and perfectly acceptable. Of course, if I find out later that they are not relating well or need to learn more about respect and such, and so need to adjust their relationships or speak up about how they'd like to be treated differently, that will be fine... that's just the same as any relationship that improves with time, I figure.
Anyway, this is something that I've been thinking about a lot and I agree that it isn't so far out that any sort of relationship can exist between sentient beings who are capable of relating, who naturally relate to one another.
I actually haven't had hard communication that lasts for very long for quite some time, so I haven't heard from them explicitly save for little bits, and also through indirect communication (barriers have been put up by stronger alters). I do feel like I miss them but I know it's best for now. These kinds of relationships are not the same as between people with their own bodies and can get pretty messy (we've had some pretty bad spats in the past, and it was awful to have to endure that) so I know that we need to figure out some new rules for coexisting. It's great that you two can live together so successfully, I don't know if that's common.
I also want to add that I am in a longterm, serious relationship with a woman, with whom I live, whom is also aware of my DID. Her and I were in a relationship before I knew about my alters. When it came out that my alters felt more than friendly affection for me, it was a hard idea to grapple with, and I'm not sure what she thinks about it these days. But she has expressed love for them and I feel like she means it, whether or not they trust her yet. D seemed immediately open to formally starting a relationship with her conjunct, and like the one he considered he and I to be in. I also know that a few of my alters who don't announce themselves find her physically attractive