No wetness of .?

Please help. My wife used to be an abundance of wetness whenever we want to have , and this I love a lot. However she started noticing a reduction of the wetness after our first child in September 2000. After our second kid she stopped wetting completely no matter the . Since 2003 we have been using lubricants and we are not enjoying like we use when wetness was natural. She has ran tests and she does not have infections. Please what can we do?