Something tells me you're leaving out some important details about the state of your relationship. I think you're full of crap saying that everything was perfect up until she went through your phone. There is no way she just out of the blue decided to snoop through your phone and it happened to be at the same time you were wasting time on a dating site. She's done it before and I would bet you not only know about it, but her trust issues are something you're aware of and have been a source of contention already. The question is why does she have these issues.

I know you're only 25, but who browses dating sites just for fun? It seems like a boring waste of time to me. I can think of MANY other things to pass my time. Regardless, the fact you even set yourself up for this while in a relationship with someone that you have to have known has some kind of trust issues speaks volumes about your readiness to be married. There is no way you guys were together for 3 years and she just over night developed a need to go through your phone and then leave you.

Anyway, it doesn't sound like she's ready either and has some major trust issues to get a handle on. Just because you love someone doesn't mean you are ready to be married.

Just leave her be and let the pieces fall where they may. What else can you do? Good luck.