Entering and Re-entering the Netherlands

Here is my situation:

I will have a residence permit while I go to school for a year in Leiden.  My boyfriend would like to come live with me if that's at all possible.  He will not be applying for any visa because he will not be trying to find work.  He can only stay in the country for 3 months max as a tourist.  How long does he have to leave the Netherlands (or EU) in order to come back to the Netherlands and live for another 3 months?  We will also be traveling in the summer to other Euro countries.  Will this be a problem?  Any info will help.  I've looked at a whole bunch of government websites and all just tell you to how long you can stay or not.  Of course they won't tell me how we can get around him getting a visa.

Thanks

I am pretty sure that he would have to be out of the EU (European Union) for 3 months after the 3 months he would be staying here.  To confirm this, you should contact the IND (Dutch Immigration Office) for more information.  Good luck!  Leiden is a great city!  :)