Hi A, Some women don't bet wet during foreplay, your find its quite a common thing, you could try putting yourself on some vitamin B 6, I read a very good report for it worth a try.
But a question is how much foreplay are you getting before sex, you don't need a wam bam think you mam type of sex, try a nice slow build up, make sure you man is getting you wet.
Good Luck
If you're not excited during foreplay, I'd look at a new partner.
Well if the body is not doing the job then you can use a water based lubricant.