Adjusting to a new bundle of joy is never easy no matter who the parents are, how "perfect" the baby is or how much help and backup you have. Will himself remarked on having sleepless nights and that George was an active baby. Along with adjusting to the new addition and the diapers and the bottles and the spitting up and the 3 am feedings, you realize that the world has not come to a stop. Jobs still have to be done, groceries do not buy themselves and it is not unusual that a new mother gets into "moods" now and then. Why would it not be the same for Will and Kate as new parents?
After 2 weeks paternity leave, it was back to business as usual for William at work. He has a very demanding job which does put a lot of restrictions on him. Those restrictions are not only to ensure the safety of the aircraft and his crew but also ensures that he is clear minded and able to make quick snap decisions.
This couple has known each other and have a mature enough relationship to know that they don't have to be in each other's pockets 24/7. In fact, I think most couples find that when they are continuously together, it can get stressful and they need a break from each other. Ask me how I know. Mr. Remote is retired here and its been quite a long time since I've had "me" time. I'd love someone to take him away for a weekend or so.
We have to remember too that there's another little stress factor involved right now. It usually is prescribed that a new mother give herself 6 weeks at least to heal after having a baby and that could really leave Will kinda chompin at the bit and to be honest, a good stag party is the perfect prescription for letting off some steam and just plain having fun. We don't know but its very possible that Kate has also had some "hen" time away with her friends. That's the beauty of having a strong support system intact.
It won't be long till they're settled in KP and fall into a routine that suits them and George. Its all part of married life.