They need you. Time to give up the booze.
You said your GF was the one on the Left. She's quite the looker. You are a very lucky man to have the little hottie, especially if she was able to keep her figure after child-birth. The anger in your heart is because you wont forgive her...or yourself.
Open up to her, tell her why you WERE angry, that it is past, and your family is what is important to you now.
And give up the booze. A beer at dinner or watching the sunday game with the boys is cool. Drinking to blind drunkeness leads to stupid decisions, hurt families, and your own poor health (not to mention financial issues; ever add up just how much money you can waste on a night out?).
While many here scoff at religions, faith in something can be a great stabilizer and a calming influence.
I wish you luck and hope for the best for you and your new family.
YOUR family. In the end, they will bring you the greatest joy and happiness you can ever find.
Peace brudda.