HELP ME!!! Guy Probs!?

Ok so lately in my life there have been a lot of guys, including this one I met a few months ago that was really promising, but he ended up a total dud. I haven't had a boyfriend in 2 years now. I decide i'm not looking at the right type of guys, so I scroll through my contacts and an old name pops up. Garrett and I hadn't talked in so long, that he actually almost forgot me! I'm a teenager now and Garrett is a year older than me. We got to talking and soon I found that there was something between us that wasn't there before. I really like him and by how much he flirts, he really likes me. Sounds promising right? Well it was at first, until I met another old friend, MarieAnn. Turns out MarieAnn and Garrett had hooked up about a week before I texted him. MarieAnn was an amazing friend way back in elementary, but come on it's high school now. I know Garrett likes me a lot more than MarieAnn and she only thinks of him as a friend really because they were hooked up by the quarterback without really wanting to go out. Simply just because they didn't want to be single in summer! Now that MarieAnn remembers me, she wants to go back to the friendship we used to have but meanwhile, i'm diggin on her man and normally since she doesn't really want him that would work. Except that she's head cheerleader soo if he breaks up with her, even if there is nothing there, she will make his life miserable, maybe even mine. Knowing her, she'll keep him all summer as her pet, but what if I can't wait that long? What am I supposed to do?