This is it. Tell her how you feel and the examples you gave here as to why you feel that way. If she has nothing to hide she will offer her phone to you. If she doesn't do that and gives you a bunch of excuses or just tries to tell you that you're being silly, then ask her to prove you're being silly to put you at ease. If she won't, then no need to look in her phone. You won't like what you find anyway. Just know that she's at least already started flirting with some guy, and more than likely that guy is DPing her with his best friend right now. But tell yourself it's just a little flirting that hasn't escalated yet so you don't get all mad and shit. But we all know she's getting trains ran on her by dude and his bros.
Either way, the only way you will feel better is by posting her noods here on EF.
Oh, last thing...only do all this after you have given her the fucking of her life. Make sure you put it in her ass and make it hurt. Choke her while flushing her head in the toilet, then shit on her chest if you really want to go out in style. It's the only way bro.
post pics of all that too.
YWIA
GICH