Tabloids and the Downfalls of Celebrity Relationships

It's a viscious cycle.  Two celebrities get together.  It's highly publicized but in a positive light (with the exception of Britney Spears and Kevin Federline).  Couple gets married or moves in together.  They have a biological child or choose to adopt.  The tabloids take photos of the happy family....

And then the inevitable happens:  the tabloids turn on the couple reporting that they are on the rocks or about to split up or are jealous of one another's careers (I can list a whole host of other stories I've passed on news stands).  Reps from both his and her (or his and his, or her and her) sides come out saying that they are happy and still a strong couple.

A few months later we find out the tabloids were in fact correct in predicting the demise of the relationship.

Cases in point: Nick and Jessica, Britney and Kevin, Christie and Billy, Ellen and Ron, Brad and Jennifer, Vince and Jennifer, Shanna and Travis, Reese and Ryan, Carmen and Dave, Liza and David.  The list can go on and on and on.  For these couples it was all the same thing: happy marriage, sometimes with children, positive publicity and then BOOM!  The tabloids announce trouble, publicists come out swinging and denying, and a few months later it's over.

On the other hand, you see couples like Catherine and Michael, Beyonce and Jay-Z, Heath and Michelle, Christina and Jason, and Jennifer and Ben in happy and seemingly healthy marriages.  Keep in mind also, that aside from BEyonce and Jay-Z, the couples listed in the still together list don't get photographed nearly as often by the paparazzi as the torn apart couples do.

So here is my questions to you, or questions:

Do you think the tabloids are what is causing celebrity couples to split by causing tension, or do you think these people marry or get together just for the heck of it, for publicity reasons?  Do you think publicists should just stop trying to deny rumors of a breakup or divorce?  What do you think the deal is with the celebrity relationship cycle?