Hi Jackilyn,
since I seem to have inspired this post to a degree just wanted to respond that I don't think integration is necessarily the be-all and end-all - it is definitely a personal choice a system can or cannot make (much like marriage

)
Just for the "sad and lonely" part: for me it is nothing like that. I.e. it is not like "I" am suddenly left on my own while everyone else is gone and I have no one to talk to in my head. It actually feels less lonely than before because we are less separate, we are one (some, there's still some alters left "out there" who will need more time and healing).
We don't need to talk that much any more because we can experience each other's thoughts and feelings immediately, without language as a "bridge". No one "died" or disappeared - we have the same consensual decision making process as before, but it works much faster (i.e. instead of having a two hour meeting to talk about what to do, we just fuse all our consciousness streams into one instantly).
We ultimately decided to integrate because we felt that even with the great degree of cooperation we had, everyone only got part of a life. This way, everyone gets all of it. But then we were all communists to start with, so no one was particularly attached to their individual separateness

Another reason was that we wanted to see if our dialectical structural model for integration works - it did, for us at least. We might try and write up the protocol for the use of others who might want to try (I'm fairly sure it would work without drugs as well, only perhaps would take longer). But one thing I've learned from this is that multiplicity seems much more a spectrum rather than an absolute singleton vs. multiple binary. No one is completely unified - it all depends what level of fragmentation is workable for someone while still allowing this person (or the parts of a system) to be happy and content.
It shows an excessive tenderness for the world to remove contradiction from it and then to transfer the contradiction to reason, where it is allowed to remain unresolved.
G.F.W Hegel