Love Triangle??

Abby
Okay, I typically don't post on here. I am the type to just read what you all say. But I need some advice. I am in an incredible relationship. (Pic posted is my boyfriend and I) 
 I love my boyfriend sooo much. However, one of my best friends wants to be with me. I have made it clear to him that I just want to be friends and all, but he won't give up. My boyfriend is starting to get a little threatened by it. I have talked to my friend about toning it down a bit but he says that he's not doing anything. I love him so much as a friend. He's the one I go to for everything, and I don't want to lose him. But I don't want to lose my boyfriend either because I swear he's the one. ❤.  Anybody have any advice for me??