I wish I could help you, but there’s no way I can know what’s in your husband’s mind, why he doesn’t want sex with you, and why he won’t talk about what’s wrong. I suspect you already realize that marrying someone you knew for only six months was a mistake, and he realizes that, too. Maybe he seemed kind and genuine at that time, but refusing intimacy without explanation is neither kind nor genuine.
Porn isn’t the problem. Not being able to discuss what’s wrong is the problem. The marriage was good for one year, bad for three. If there’s anything to salvage, you’ll need the help of a good sex therapist or sex-positive couples’ counselor. Do you want this marriage? Would he be willing to go to counseling with you? Does he say anything that reassures you that he wants to stay in this marriage? This marriage is hurting you and I hope you’ll get professional advice to help you decide whether you want to stay or go. I think you already know.