You have feelings for Elizabeth that are not mutually shared. She is not interested you. You got rejected, but stuck around in the hopes that she would eventually realize her mistake and fall for you because you're such a swell guy and friend. It doesn't work like that. She sees you as nothing more than a friend, and that won't change anytime soon. You need to accept that, first and foremost. Stop putting her on a pedestal because you think she's "the one" or that you and her are perfect for each other; you're living in a fantasy. Secondly, I don't recommend you break up a relationship simply out of jealousy. Again, she's not interested in you. If she were, she wouldn't be dating the other guy. Third, Elizabeth is trying to let you off easy with all the "You need a girlfriend" talk (another big sign she's not interested in you). She's trying to get you and the other girl together in the hopes you'll get over her, which you really need to do. So to that effect, go on the date with Halle. It doesn't necessarily have to lead to anything, but just go out and have fun anyway. Who knows? Maybe you'll end up liking her more than Elizabeth and it'll work out pretty well for you. Or maybe nothing will come of it. Oh well, there's plenty of other women out there that are single; just move on and try again.