I can only get aroused if I watch gay porn, and not when I'm with my boyfriend. It seems thats the only time i get moist and its really bothering me
Severe arousal problem
Maybe you aren't attracted to your BF anymore?
Like sdp said, maybe you aren't sexually attracted to your boyfriend anymore.
Or maybe you just aren't into what he's doing. Has he tried something new you didn't like? Is he just doing the same old thing?
It could also be a lower level or hormones, stress/anxiety, or maybe your body has just had enough sexual arousal from watching the porn and isn't going to feel very "ready" later.