Why does everyone have to speculate so much?
Isn't it plausible enough that Georgie was ready to settle down and Dec wasn't, causing them to split? Maybe he felt she wasn't the right person? Better to split than have her walk down the aisle under false pretences.
People speculate because they speculate. Better than gossiping about the neighbour. Celebrities are a media invention to get people talking about them rather than focussing on the important things in life. We're not gossiping about stuff which would peeve the powers that be. Celebrities know it comes part and parcel of their status.