I need some advice

I've never read anything about this and I've gotten pretty interested in reading some of these topics and questions so I thought this may be a good place to see if anyone can relate/any advice 
I'm not sure if my SO has ever noticed it really, but him and I will be going through foreplay and I'm very into, I love doing stuff with him, so don't think that he's doing any bring wrong...
But someone's it's like I can't stay wet..I don't know if that's a normal thing or happens to other females or not. But I will be so turned on and everything feels great but sometimes I swear I just can't stay wet. And sometimes it really kills the mood. 
I've thought about asking my gyno, but I'm not gonna make an appointment just for that, may just ask her at my next checkup but I just haven't heard of that being an issue for other women really. Any thoughts?!