>>I’m just wondering if there are any other ways to go about this.

You’re asking if there’s any way to avoid the consequences of being a total piece of shit, and the answer is no.

Hiding this will absolutely blow up in your face. If you want any sort of chance with your current girlfriend, you are going to have to tell her. And you’re going to have to watch it completely destroy her. And you’re going to have to do anything she needs you to in order to help her heal, even if it means leaving her.

If she does decide to allow you to try to make it up to her, just know that the person she sees you as will be completely altered. How she feels about you, how she feels about herself, how she feels about intimacy, how she feels about the relationship, her trust in you, her love for you, her patience and understanding with you, will all be changed.