Papapete, Welcome, the short answer to your question is NO, don't dilute your wine. Like Rocky, Dan and Wade E said more info would help. But short of that, Blending is the best way to lower sweetness. In my opinion in this order, a dry blueberry (won't change the flavor), a dry red (something like a Shiraz or Merlot) or last ferment some welches white grape to dry and blend it in.
(disclaimer: this answer is base on the assumption that all steps to proper wine making were followed)