They've been married for years, she should know by now that flat denying Henry from something doesn't work. Obviously the answer is counter trolling.
After realizing money CAN buy her love from the masses, Isabella's heart grows three sizes and she also starts spending money on charity. But wait, if there's two black holes in the bottom of the treasury where's all that money going to come from?
Well, now that Gallia's not preparing for major war and the Albion campaign ended in peaceful annexation instead of whitewashed conquering... There's really no need to keep expanding the military. Maintain it, sure, but the bottomless budget it had for research and such under Marshal Henry is no longer necessary. Henry clearly agrees that the priority should be on aid now.
The military can tighten its belt a bit for the sake of starving war orphans, right?