Desmond does this, and it is really annoying, he seems to think, oh Mom is here I can nurse rather then drinking my water. While I don't have a problem with nursing, I really thought that after 12 months or so nursing cut down some to 3 to 5 times a day, I am happy on days when we nurse less then 8 times and 10 times a day seems normal most days. I will stop nursing if he pops off more then 6 times or so in a short period though, since he isn't really nursing at that point in time, he is just playing.
I have stopped offering to nurse other then naptime, bedtime, and in the morning (he nurses 3 times before we get up in the morning), just because I really do want him to cut down a little. I never refuse when he comes and asks to nurse though.
I really think it is boredom here too, because when Daddy is home he nurses a lot less, and when we go out to do something all day, he never asks to nurse. Fortunately with the weather getting nicer now, we can go out more during the day to take walks and such so maybe that will cut down on the constant nursing some.