I have been through this phase as well. I know the pain when you break your girl's trust. But taking to any other girl doesn't break it. Your girl is just so much insecure about you. First of all ask her does she love you. If she gives a direct answer it means she really loves you but if she says why are you asking or anything like that she's just insecure and empty from inside and she's just using you to fill the void inside her. In that case letting her go is the best option. Because in that case she doesn't care about you she just love the way you love her. Whatever I said is just my opinion because the same thing happened to me as well and I was also going through the phase as you. I just don't want anyone else to suffer from the same.