First...
... I don't think that C/L mean us to see Justin and Brian's separation as anything but another stage in their relationship. As I've said elsewhere, this is about showing how things have changed from the end of S4 (because if Brian doesn't let the move to LA throw him for a loop, then I've completely misread Brian for four seasons).
At the end of S4/beginning of S5, Brian is bound to go back to the "well, he was going to leave anyway, it might as well be now" space, and, drama queen that he can be, do the whole, "it's over" routine.
But, to me, it sounds as if by the end of S5, it's very far from over, even in Mr Kinney's mixed up self-destructive mind. It's a bit of a detour, that's all.
And I don't think we bj fans can have it both ways - we either say that they've been through tough times before, and, having weathered those, are a strong and loving couple, who can deal with this situation and still come out of it intact, or we say that the only things that have ever held them together has been propinquity, opportunity and sex. If they have the sort of deep, meaningful, one might almost say karmic, connection that some of us believe they do, then this is just another phase of their journey together. It's not threatening, unless they have the very shallow, sex-based relationship that many BMers have accused them of.
Justin going away, and Brian still being prepared to open up to him and to make the emotional commitment that he hasn't been able to make, or at least to articulate, so far, is the most significant way that C/L could find to make the point about how far they've come, and how strong their relationship is. We have to give Justin a little credit here. We have to trust him not to let Brian expose himself that way, and then just give up on him, and on them. I believe that having finally won what he's been fighting for for five seasons, Justin will fight with everything he has to keep faith with Brian, to keep their relationship stong and loving, and to work out a way for them to live out their love for one another, even if, for a while at least, work is going to keep them in two separate cities.
Second ...
... monogamy. I don't think that monogamy per se is all that big a deal to either of them. I think emotional commitment is. I suspect that the fact that Brian is both hurt and threatened, when, after finally asking Justin to move in with him, Justin confesses that he's already accepted a job in Hollywood, without so much as a "guess what?" to his "partner". And that, being Brian, he'll pull back emotionally when Justin returns. I suspect that it's that emotional distance that causes their problems in S5.
Here's how I read the beginning of S5. Brian pulls back. Justin gets frustrated. Brian, in a fit of pure self-destructive, "I'm Brian Kinney"- ness, goes into the competition with Brandon. There's the syphillis thing which, I think, is symbolic, not of Justin being afraid that lack of monogamy is a physical threat, but of the competition being sick, and of it revealing a sickness in Brian that he feels the need to get involved in it. (Which harks back to the S4 conversation in Babylon about why Brian tricks.)
They both behave like the drama queens they are, until the bombing makes them re-assess. And get real. The marriage isn't real. It's about rings and ceremonies, not about them, not about the reality of their feelings for each other, nor about how their lives are going to be. So their not going through with the marriage is symbolic not of lack of commitment, but of them keeping things real - for them. I don't think that Justin plans to go celibate in NY, any more than he did in LA. Nor would he expect it of Brian. What I think he would expect is that Brian will not use his "sex as pain management" to distance himself emotionally again from Justin. That he'll do what he needs to do to get through his day, and then phone his partner and, in Kinney speak at least, tell him that he loves and misses him. And he won't try to throw Justin off any damned cliffs. I think that's what the end of S5 is about.
Third ...
... I know I'm Brian-centric ... but all the crap that's been floating around makes it all sound like it's purely up to Brian getting his act together for them to work.
Hello?
Are we really saying that Justin never gets it just plain wrong? That he's the model of wisdom, rectitude and perfect behaviour? That at least some of their problems haven't stemmed from things that either Justin has done, or has failed to do? Because if that's how you've seen the last four seasons, then we've been watching different shows.
Brian emotionally unavailable S2 - Justin lies and cheats with Ethan (while living in Brian's loft, off Brian's money, I might add).
Brian caught up in the Stockwell thing in S3 - Justin lies by ommission about what he's up to with the posters, and puts Brian's career at risk in the process. One of the most perceptive lines I've read in an S3 fanfic was by someone (apologies, because I can't remember who) who had Justin say that he didn't regret working against Stockwell, but he should have left Vangard first. That he didn't do so was dishonest no matter who owned the agency, when Brian was one of the partners, it took dishonesty to a whole different level.
And S4 Justin I don't even want to go near.
The whole pink posse thing - and how he treated Brian during it. Because there was no indication at all that Brian's feelings counted for anything with Justin during that phase. Quite the opposite - he was often deliberately hurtful to his "partner". He was every bit as selfish and self-absorbed as Brian at his absolute worst.
The way he didn't stand up for Brian during the whole "slap" fiasco.
The way he didn't even seem to think about Brian, about Brian's situation (um ... remember, just recovering from life threatening illness?) before he joyfully accepted the job in LA. Let alone discuss it with his partner first. (A simple, "Brett, I'm fairly sure it's going to be 'yes', but I do need to discuss it with Brian first", would have been nice.)
The way I see it, after he accepted Brett's offer, every minute that Justin let Brian go on thinking that nothing had changed he was lying to him. I know that sounds harsh. But I also know that's how I'd feel if my partner accepted a job on the other side of the country and left me blithely making plans that included him when he just wasn't going to be there, and didn't even have the grace to tell me that.
Candidly, I'd be surprised if Brian didn't have difficulty believing in any kind of "ever after" with Justin after he's already been cheated on , and lied to, and left (twice).
I'm not flaming Justin.
I'm saying that both of them have a lot of growing up to do. It would appear that in S5 maybe they both make some headway.
That's how it sounds to me at least.
And, although yes, I'd like the last scene to be them together in the loft, shutting the rest of the world out (a final scene of Brian replacing the locks would have been perfect to me), I can live with this.
I think.