Yes, he's trying to use her to fulfil his carnal needs. One could argue, though, that that's part of the "package" in a traditional marriage.

We promise to be faithful to our spouses, and our spouses promise to be faithful to us. In exchange for that faithfulness, I think it's important to recognize that our spouses have needs too.

No, she shouldn't feel pressured or allow her husband to do something that she's not comfortable with. Yes, he sounds a bit thick headed.

Still, he's trying to give up porn (a good thing, I would think) and he wants her help. If she doesn't mind helping, then what's the harm?