I Cheated On My Wife With A Colleague

I am a software engineer and married. I cheated on my wife with a colleague at work, someone in the same department as me. It was never meant to happen, but there were some late nights where we worked together closely, and one thing led to another. We both knew it wasn't right, that our jobs were too close for this kind of involvement. Now I feel terrible every time I see her at work, knowing what we did behind my wife's back. It was a mistake and I regret it deeply.