Dear Sister, if all possible you need to get rid of your internet service. The bible says, "if your right hand offends you, cut if off".
My mother had the same problem w/ her husband, so she had the internet turned off, and if he hadn't agreed to it, she was going as far as divorcing him. Your husband is not be faithful to you, and he has to realize it and decide what's most important.
I pray that the Lord will give you wisdom and understanding if what you should do about this situation; Furthermore, touch her husbands heart and bring strong convictions upon him. Open his blinded eyes and show him that this pornography is a work of the devil and that it will eventually destroy his family and his life. Lord, bless this marriage and restore it with love and hope, in Jesus name I pray.