I think that if she is going behind your back with another guy and lying to you about it deleting every trace of him as she goes and this has been going on for a year, then maybe you should end it because if she loved you as much as you love her, and if she knew how much you love her, then she would have been able to tell you thins in the first place like it was no big deal, and it would all just blow over

but then again i think if my bf was doing that then yeah id want him to tell me but i wouldnt be able to end our relationship, but i really think its the best thing to do. ive just learnt through bad paranoia, that i cant trust anybody, but im asking you to trust me now, just end it with this girl because if she really loved you she would have never gone to that guy in the first place let alone kept it a secret from you.

im probably not helping but im just putting my point across.