My husband has a porn addiction and wants me to act out scenes. Should i?

Any addiction. Is a problem. He needs treatment.
Mutual consent. Sexual variety is part of the spice of a relationship. But all such activity requires a strong commitment to the desires of both partners, safe conduct and no abuse. You should have a mutual desire for these things; it cannot be through bullying, threats of loss of interest in your relationship or anything like that. Hopefully your husband will be receptive to such a discussion.
12 step program +. Therapy plus a 12 step program should help, if he is ready. For you, there are support 12 step programs too al anon, s anon, etc. Get help for yourself, and he might come along - but you don't need to suffer anymore.