Getting wet

When me and my S/o have sex I am wet in the beginning but as we progress I get dry... it's embarrassing and I didn't not know what to do. He doesn't seem to mind because he just adds saliva, but even then it wears off and sex becomes painful... Idk why I have this problem because I am usually the one who makes the first move and I am always turned on while having sex...Does anyone else have this problem?Any tips on how to stay wet?