I'd say so for someone who has moved on with their life. She obviously didn't have the depth of feelings for you that you had for her, or she wouldn't have cheated on you.

Is the guy she's seeing now the guy she cheated with? The fact that she's in another relationship makes it unlikely the two of you will be getting back together, so I'd advise to to try and move on too. You're still young. It might now seem like it now, but you'll find someone else to fill that void in your life you're feeling now.

Whatever you do, don't let yourself get pulled into doing something stupid that's going to land you in jail. Been there/done that, and she will continue on with her life while you're sitting in jail like nothing happened. It's something that could potentially follow you for years, depending on the charge, and you could be living with the consequences of your actions long after she's forgotten about you.