My boyfriend, to me, is easily a 10/10. Sometimes when I look at him I can't believe how attractive he is and it makes me super insecure. Girls flirt with him all the time and I know he could have anyone he wanted. I have no idea why he's with me, I'm average at best. It makes me really scared that he'll find someone better and more attractive and leave. I know he could do so much better than me which just makes my anxieties worse. Whenever he talks to any other girl my BPD flares up, especially when I can tell she's flirting with him. 

Does this happen with anyone else?