The fact you even have to question that statement, shows your level of maturity. You are still a kid. Do the right thing end it.
Oh and there's two kinds of cheating kid.
1 emotionally cheating on someone--- oh hi that's you! Yes even if you only go on one date, and order the low fat double whip latte. And only look at her once, in the left eye. No matter what you say. It's a form of cheating.
2 is the big physical
Be a man, and be accountable for your own feelings and the feelings of those that surround you.