What does yor experience say about this???

It has often been observed in relationships that the girl complains that the boy used to spend more time talking a lot all the time. But as the relationship gets older, the boy doesn't give much time, he used to be free all the time, now when he is busy, he has an excuse.

Things didn't end all night, now there's nothing to do !!

After all, what could be the reason for this? Does it happen in every relationship or does it happen with some people? Do people get bored quickly or do they really run out of things ??

What does your experience say about this ??