If you feel as if your lover doesn't find you attractive enough, if you feel as if you're not getting enough sex, then you will eventually feel as if there is something wrong with you, even if there's not. Your self-esteem will suffer. At your age and your boyfriend's age, you should be able to make love more than once a week at most. You are at the horniest age and so is your boyfriend. If he isn't interested in making love with you as much as you want after just four months, then you have a serious problem, and it has nothing to do with his masturbation or his looking at pornography.
Many men masturbate and have lots of sex with their partner as well.
If your boyfriend can't be the lover you need, then you need to find a new boyfriend. Don't beg him for more time or more sex. Begging is demeaning, and frankly, not very sexy. If you want sex and he doesn't, then leave his house. Don't hang around and allow yourself to be put down by being rejected.