Originally Posted by Baraka_Guru

You are both at fault. There is no need or benefit to measuring who is more at fault because it doesn't matter. You both failed "the test." That means neither of you passed; there is no degree of failing--you both failed.

Both of you spoke untruthfully to one another. Both of you engaged in sexual misconduct. Both of you did something that would cause the other to be hurt and become miserable.

The best thing for you to do is tell her the truth immediately and work out the problem as it comes to you. Whether you can salvage the relationship depends on the maturity and commitment of both of you. The longer you let it go, the worse it will get. Nothing is beyond redemption if you put in the effort. To disbelieve that means you are too pessimistic and would suggest to me you aren't ready for a serious long-term commitment... with anyone.