I'm so sorry, Stacy. I know the feeling of wanting to believe the fairy tale when they promise to stop only to flung back into reality.
My ex promised to stop drinking days after our child was born and lasted about two days until I found him chugging beers and a bottle of vodka on the back patio when he thought I was sleeping in between feedings.
It's a betrayal for sure. I recommend you think about what boundaries you want to set for yourself and your children going forward before you speak to your husband. Be prepared for the excuses too. At the end of the day, just listen to yourself because that inner voice is important.
Sending hugs to you.