He knows you know. After a while he stopped trying to even hide his cheating knowing that you'd just let it happen for whatever reason. He continued coming home after being with the other woman and acting like nothing happened even when you confronted him.

Right now he's on a date with his side piece not even bothering to do so in private. He's confident that you won't do anything about it. He's confident that you're still madly in love with him.