My boyfriend, husband, and I live together with our kids.
I can't imagine typing out an answer that would be concrete enough to describe accurately right now. But on this board, there is a blog page-and I have a blog on there that explains a lot (as do many other people).
Since things are going ok, and you are curious about long term plans, but not seeking solutions to immediate problems (which is AWESOME!) I woudl HIGHLY suggest checking out the blogs section. You will find a lot of concrete examples of situations that arise in various circumstances and how different people resolve them. There are so many possible solutions to the myriad "problems" that can crop up in any type of relationship; it would probably be more beneficial to dig through there, where you can decide which people seem to be most like what you guys are and may have the best examples of how to work through whatever arises.
Congrats on making progress together!