Sorry, wrong number
So, this guy made a shambles of things. They determined to split up with their girlfriend when they realized that the relationship wasn’t working. They should have double-checked who they were texting before they sent the message because instead of texting their partner, they ended up sending it to their wife.
He also admitted to having sent the text to her, not someone else, while acknowledging his prior transgressions. We suppose that’s what you get for cheating on your wife and attempting to maintain too many secrets.