You want the DM to stop removing your buffs...stop buffing.
Technically since no one can actually tell if you're buffed unless they have Arcane Sight there's no reason for them to lay 6 targeted Dispels but heck if your DM is doing it just switch your spell list to a more offensive list and Flame Strike your way to fun.
It has to be pointed out that an enemy cleric with a properly worded divination knows all he/she needs to know with regard to these sorts of things - unless your party is paranoid.
My aim here is just to point out that the DM can easily excuse such knowledge on the part of NPCs. I still think the OP is best off talking to the DM and telling him that his dispels are excessive and make things frustrating (assuming that's what's going on.)