Prince william stated he enjoyed getting his freedom back after the break up...what does that mean?

People are social animals and we are all looking to make connections with people - presumably that's why wills starting dating kate. I am a 35 year old bloke - but don't understand what blokes mean when they say having a girlfriend restricts their freedom ? Surely blokes can do the random sh*gging thing before dating a steady girlfriend (some do it on the side) - so what do blokes mean by this?