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.
Whoever has committed Zina (fornication or adultery) is obligated to repent to Allaah and conceal his sin and he should not inform anyone about it as we clarified in Fataawa 83573 and 84052.
Therefore, if your husband had committed Zina, then it is not permissible for him to inform you about what he did and it is not permissible for you to ask him about it. In case he repented, then whoever repents, Allaah accepts his repentance. So, you should not preoccupy yourself with this matter.
As regards what you mentioned about him that he watches pornographic films and masturbates, then if he really does so, he is wrong and sinful. Both matters are evil as we clarified in Fataawa 103113 and 95510.
In the above-referred Fataawa, we also clarified what a wife should do with her husband in the above cases, so please refer to them.
Allaah Knows best.