Oxy's are very addicting and if you suspect addiction, you're probably right.
And YES, narcotics can definitely mess with sex drive.
If you want to be w/him through this, just try your very best to be supportive and give him the opportunity & help to get off the drugs and get better. Otherwise, I agree with the person above, if he isn't ready and willing to stop, you need to decide what is right for you. It sounds like he hasn't been on them too long, so it's best to get him off now before it gets worse.
My question is, why is he looking at porn, but not having sex w/you?
Lowered libido and sex drive IS a side effect of opiates. You can not make your boyfriend quit. He has to WANT to quit or it won't happen. If you push him you will push him away. Approaching him in a loving concerned way is going to do more than making ultimatums and refusing to be in a relationship with no intimacy. IF he is addicted than he needs you more now than ever. Opiate addiction ***** the life out of you and if he is addicted he is in for a HARD road. If he is not than with love ask him to please stop. If he doesn't then you need to decide what is right for you.