Can't get wet enough...

Its gotten to the point to where my SO pointed out that I don't get as wet as I used to and it's resulted into us using lube and even then it's hard because we change positions a lot and often. We are trying to TTC and it's upsetting. I cried because he didn't finish tonight after making the comment and an embarrassing pause to re-lube. Does anybody know any vitamins or anything to help?