All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
First of all, all perfect praise be to Allaah, Who guided you to Islam and we ask Him to make you firm and steadfast on His Religion until the day you meet Him.
Undoubtedly, it is not permissible for a Muslim to visit pornographic sites. If your husband did so, he has indeed committed a sin.
The first thing that you may do in order to turn him into a righteous man is to earnestly supplicate Allaah to guide him. If he repents, it could be that this will solve the problem of him wanting intercourse every night.
The scholars stated that the wife is obliged to respond to her husband when he calls her to bed but this is conditioned on her not being harmed by this. If she is harmed, she is not obliged to respond to his request. Therefore, your husband must take this into consideration, because this is treating the wife with kindness and this is an Islamically legislated matter.
Therefore, we advise you to counsel your husband in light of the above and choose a suitable time for doing so. If he is able to marry a second wife, then you should advise him to do so, accept this from him and seek for him a pious woman for marriage.
Allaah Knows best.