That's easy to fix, well it was in my case.
I told a friend about this problem and she advised me to buy a chastity device for him. He likes porn right?.
So I ordered one. I showed it to him and told him that would spice up our sex life.
So he agreed to try it. I put it on and locked it. I hung the key around my neck on a chain.
He thought it was fun. Anyway He complained at night because he had an erection and complained that it was uncomfortable. I unlocked it and he made love to me.
The next day when I got home from work I asked if he would wear it again. He wasn't so keen. Anyway I persuaded him and he did. The same thing. In the night he complained. This time I cuffed his hands to the bed head before removing it. I sat on top of him and made love.
After that he wanted his hands uncuffed. I said sure, but the chastity thing has to go back on first.
Anyway to cut a long story short.....It only comes of now when he's cuffed and I unlock it. It always gos back on before the cuffs come off.
He can't masturbate with it on at all, he can't even get an erection . Instead of watching porn he does house hold chores and pampers me in the hope that I will remove it and give him some relief.
It's worked that way for 3 months now. the first month he was mad at me but now I am the one who allows him relief and he does his best to please me in the hope that I'll release him and bring him to orgasm.
It's kind of like having a pet man.
That's my advice.