(X-post from /r/relationships) Boyfriend has a female friend who is a perfect person and would be a better girlfriend to him than me

... in my opinion, anyway. She's smarter than me, slimmer than me, more hardworking, loved by everyone, she's so successful in life, she is pretty, everyone thinks of her as the most caring, loving, kindest girl ever... she's not "crazy" (as my boyfriend has called me several times, because he was mad though so idk) and her family and my boyfriend's family are SO SO SO close. They spent like every waking moment together in their childhood, up until like a year or two ago, but even now, they are super close. I'm constantly being told how my boyfriend parents love this girl so much and they would love it if he married her. They hate me so much... I don't even want to go into the details of that but basically, they hate my family AND me (for various "reasons"). I can't ever bring this up with my boyfriend because he just yells at me and says that he doesn't know why I'm worried. He only says good things about this female friend of his, never anything bad (there probably isn't anything bad to say about her though; she is flawless, so perfect, and nothing like me). About me, however, he can state so many flaws. I got angry a few times and asked him why he loves me, why he didn't just ask her to be his gf instead of a loser like me, and he couldn't answer. I pressed him for an answer once and he said "I don't know" ... so yea. I hate being me. No one likes "me"... everyone likes her. My own parents even think she's better (and better for him) than I am. Everyone thinks I'm a loser, no matter how hard I try. My boyfriend probably wishes that he was with that female friend of his instead of me, right? He's already told me that she's smarter, prettier, more fun, funnier, nicer, etc... than me. What do I do?

TL;DR - Boyfriend is everything I want. Boyfriend has a PERFECT female friend who he has known forever and is everything he could ever want and need BUT he is "stuck" with me instead, in my opinion. When asked, boyfriend can't even tell me why he loves me, can't even say something that he likes about me, something about me that he loves. I feel like crap. It feels like everyone is against me; I don't feel loved at all. What can I do? What should I do? I just want to be happy, and make those in my life happy as well.

EDIT: I am 18, almost 19 years old and female. My boyfriend just turned 23.

EDIT: We have been together for a bit over 3 years now.