Only wet for him?

Whenever I masturbate on my own terms, meaning without my boyfriend near or “not for him”, I cant seem to get wet. Ive tried watching porn and just imagining fucking him when I masturbate, but nothing seems to work. I dont get wet by myself only when I am with him and we start kissing, he caressess me etc. Its not such an issue but it does bother me a bit. Id like to know if its even normal?

Anyone any suggestions?