Now that I understand your concept of spouse relationships more clearly, I think they would work for those users like yourself who might have so many parents and/or children attached to one thought that it becomes desirable to break it up into two or more spouses, each hiding the non-relevant links from the other(s).
I would do this by making them all jump-linked to each other, rather than child thoughts of a central parent. In this way, for example, with A as the active spouse, one can see that it has spouses B and C, though their links are hidden until you click Expand All. Then you see all links for all spouses (or is that allspice?), which is better than having to activate each in turn.
Maybe create a link type named spouse, give it another color and make it slightly thicker so it stands out, so there is no need to assign special types to the spouse thoughts themselves, only to the links connecting them.
I think this would satisfy what you are trying to achieve. A, B and C are at an equal level in the hierarchy. They could share the same type and the same name, maybe with a number suffix, e.g., rename them A, A, A. Or they might all be named A and you could create 3 or more types, Alias1, Alias2, Alias3..., each with a distinguishing icon or color. This enables you to distinguish between them in Instant Search results and make the correct choice.
I don't know that I can add much more to your concept unless the developers decide to implement it. Good luck with your idea.