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, we ask Allaah to make a way out to your difficulty and reconcile between you and your husband, as He is The Most Generous.
You should know that in principle a Muslim is innocent and one should not be suspicious of what a Muslim does. You should be very careful of the devil who would make you see things as if they are a reality while they are actually not a reality and he would make you see what is not intended by your husband as something intended in order to spoil the relationship between you and him. Indeed, such whispers could lead to a psychological harm and disadvantages which you never expected.
However, if it is confirmed that your husband does what you mentioned in the question, like looking at marriageable women and looks at girls with desire, in addition to him watching pornographic films and the like, then there is no doubt that he is negligent and does abominable things. Therefore, we advise you to be patient with him and you should advise him in a soft and good manner. Moreover, you should earnestly supplicate Allaah to guide him and turn him into a righteous person. For more benefit, please refer to Fatwa 83052.
Nonetheless, you should not ask him to divorce you because of those sins, but if you are really harmed by staying with him, in this case you may ask him for divorce even in return for compensation in order to repel this harm. However, you should not hasten to ask for divorce unless you balance between the benefit of divorce and the benefit of staying with him as his wife, especially that you have a child from him.
Finally, we advise the husbands to remember the Saying of Allaah (which means): {And live with them in kindness. For if you dislike them — perhaps you dislike a thing and Allaah makes therein much good.}[Quran 4:19], and the saying of the Prophet : "A male believer should not hate a female believer; if he dislikes one quality in herself, he would like another quality in her." [Muslim]