We are a happy couple with a good sex life.
Are you sure about that? Happy couples usually don't go sneaking around and having affairs. And they certainly do not intentionally cause emotional distress to their partner.
To me, it seems you're still quite angry about her affair and still want to inflict damage to your marriage. Having an affair may seem like the perfect revenge but in reality, it's far from the truth.
Why do you want to blow up your life in this way?