She needs to do some internet research and learn that this is a perfectly acceptable condition. All you did was stimulate her body to do what it was built for. There are relationships centered around adult nursing and you can learn about that at a site like FetLife. Surely you guys can obtain a breast pump (hand or electric powered) at Amazon, eBay etc.

Now a constant flow can be annoying for the woman, and if she cannot accept the condition as it is, there are pharmaceuticals that can be prescribed to shut off the flow. In any event I wish you good luck with this and hope you two can reach a mutual understanding...with our without lactating.