This is a hard situation that I myself went through with my husband. I've been married for 4 years and with him for 7 years/ It was a struggle for him for years, since he first saw it when he was 11. Porn is something that many deal with and it is very hard to get out of. When we got married we had sex but than he would also masterbate, and I would never say no to him and I did what ever he wanted me to do. I was so frustrated that I let it in our marriage. So we would watch it together and have relations. Boy did he love this. Than I also got addicted we now we both were. I believe this had to happen so he would be completely be honest with me and now we can discuss our struggles. God has been working in our lives and by Gods grace it is out of our marriage and out of our lives. Yes, we both struggle with it but we pray together everyday that God helps us. And we talk to each other when temptation comes and it gets hard. But because we are so open and honest with each other and we now have God in the center everything has been very good. Just remeber, yes its a sin but everyone sins and everyone has something they have to deal with daily. It could be cursing, or not devoting time to God, or lieing, the list goes on. With him its the porn, you have to be understanding and just show him love. Tell him you will take him back if he promises to have a half hour devotion with you and God DAILY, Never skip a day. Show him Jesus love through this.
Do not divorce him for this. It is a stronghold on his life that he is battling, do not judge him, try to talk to him about his struggles, Tell him its okay to talk about it and let him know you will not be mad at him.
When you do your devotions, pray before you read the bible say aloud praying to God that you will both will read and LIVE the word. Start off by reading passages about marriage. Womens and Mans responsibilities. Especially the sexual one. He should not deprive you from sex either. YOu should be doing often so you both are not tempted.
1Corinthians 7 (Chapter 7 is good, But on 7:1-5 -This is key for your marriage)
Ephesians5:22-33
Another thing is church counseling, My church has a secret group of men to be sexualy pure, its for single and married men. They talk about struggles with pron and lust. No judgement just helping each other out. We are christian but we have a sinful nature that only God can help us.
I hope this help. This is what has happen with my husband and I and now our relationship is very strong and its all because of God.