I actually did have a bf when I was younger who did all he could to keep me from writing. He interrupted my sessions every five minutes for inane reasons, told me I would fail, that a woman couldn't succeed in my genre, etc. I had known before I began to write in earnest that our relationship had flaws, but his utter lack of respect for who I was sounded the death knell of any sentiment I had toward him. I dumped him, even though I was financially dependent on him at the time and had almost no friends or family to support me. I had to go into debt for a while to do it, but I got a tiny apartment in a new city, made new friends, and took classes that would help me to improve my fiction. And when I wasn't working or studying, I wrote like a fiend. That was ten years ago. I've written five books and about two dozen short stories, and I am now engaged to someone who is supportive of my dreams, not threatened by them. Furthermore, I have a group of young writers that I collaborate with and mentor.
Your boyfriend doesn't respect you, and besides that, his opinion of what constitutes good fiction is sickeningly myopic. He can't manage to rise above neckbeard fanboy in any case. Not that I think it adds anything to the discussion to tear down ASOIAF; I've known people who were like that over Dune, over The Dark Tower, over Ayn Rand, over Harry Potter. It's all a matter of personal taste, and no genre is lacking in deep, meaningful works. Focusing on one series or novel as some ideal is poisonous to one's self esteem and creativity.
OP, there are an endless number of people who will tell you that you can't succeed, simply because they are insecure or close-minded. Don't give them the time of day. Find the people who believe in you and support you. Take your class. Find your local NaNoWriMo group this November. Join a writing criticism group like Critters (and don't take all of them too seriously, just get used to receiving and considering constructive criticism, it makes you a better writer!) And, if this guy is truly the jerk he seems to be and continues to insult your very worthwhile dream, even after you've told him you're committed to your decision, then kick him to the curb. You absolutely deserve better, and the world deserves to enjoy the books you will write.
Feel free to PM me if you need someone to talk to.