Confession of Betrayal

I’ve been married for five years, and while we have an open relationship, I didn't tell my wife about the secret cyber affair I started three months ago. It began innocently enough with casual flirting online but quickly escalated into a deep emotional connection that led to regular phone sex sessions and sharing intimate details of our lives that were previously reserved only for each other. The attraction was undeniable, yet so was the sense of guilt and fear of discovery. Despite knowing I shouldn't keep secrets from my wife, something about maintaining this hidden world felt exhilarating but also wrong. Why do we sometimes seek connections beyond what's already present in our primary relationship? And how much is too much before it truly becomes a betrayal?