Is it normal for me to forgive my boyfriend?

In December i found out that he has watched porn almost every night for 7 months straight when i regularly asked him if he did because i suspected it, but he always denied it and swore o me that he didn't. One day when he went down stairs i checked his history on his laptop and all that was in their was tons of pron videos and he would go on attractive girl's profiles on Facebook and look threw their pictures. Them, after finding out that a week later i found out he cheated on me 6 months ago, and i had also asked him if he had ever cheated on me because whenever we talked about cheating he got all weird and also he cheated on almost all his other girlfriends and again, he swore on our relationship and my life and stuff he had never. i found out from all his friends and the girl. so after confronting him , and him looking me strait in the eye lying for 30 minutes he admitted it. but, i asked her if it was what really happened and she said it was not so the next day i confronted him again and after about 50 minutes of him looking me in the eyes telling me about 6 different ways of how it happened, he finally confessed. he is so sweet and nice when I'm with him and he always talks about getting married and how much he loves me and how he's changed, so i forgave him..but i still cry about him watching obsessive amounts of porn and cheating and lying so easliy to me..is it normal for me to forgive him and? i feel like he did all that because I'm not good enough, still feel this way