Hey there, I go by the first initial D, and I'm "The Top". The monkey and I have been on hiatus for a while, both trying to figure ourselves out, and our relationship, but things are going well. The time and distance has not always led to a place where one wants to write about new discoveries in yourself and your loving partner when they're on the other side of the country.
That said, we chose Livejournal for several reasons, some of which still apply and some of which do not.
First, is that LiveJournal was a community where a lot of our friends were reading. Facebook has kind of flattened this.
Second, is that we were able to make this blog something that you could add to your LJ friends list, or if you're not a regular LJ user, you could just add it to your RSS feed. Facebook doesn't offer RSS feeds, because it's not in their interest to do so.
Third, because we recognize that some people are reading this way, we post all posts full-public or full-private. We have told LJ not to publicize the list of who follows us (although for those users, it will show in your "following" on your profile).
With regard to comments, we screen them all, but mainly to protect your privacy. Sometimes, we'll reply briefly (which requires unscreening) and then re-screen.
At some point in the future we may move to DreamWidth, and at some point we may move to a private blogging setup (again, because facebook is not the thing it once was). If we did this, we'd probably subscribe to facebook as well, not as either of us, but as our own entity, just for "there's a new article" notification, for those who prefer things in their feed.
That said, the monkey and I are very much alive and well and still discovering and re-discovering each other, and I think I speak for both of us, when I say we've missed this.