Welcome, I'm glad you decided to quit, and that you came back here for support.
To be honest, huge red flags go off when I hear that someone is quitting because of the birth of a child (or marriage, or graduating college, or getting out of the military, or watever life changing event you're going through).
Some day the glow of having a new baby is going to wear off, and the stress and lack of sleep of being a new parent will start taking its toll. That's when this quit needs to be about you, and not the new baby.
So what do you need to do? Take an honest assesment - are you quitting for you, or are you quitting for the new baby? Until you answer that you are quitting for you, you have a slim chance of staying quit.
So, what do you need to do? I suspect you already know. You need to put the quit front a center in your life. At least for a while. You need to post roll early every day. For as long as this web site exists. You need to decide that this quit is for you.
As far as the 100 days thing goes, sometimes I wish that the 100 days was not celebrated at all around here. Sure, it's a big milestone, but it's not the end of anything (as evidenced by your cave). At 100 days, you understand how things work around here, and you have the tools to stay quit. But we all still need the support. becaue we are all addicts, and are $5 and a bad decision away from slavery.
So, post roll daily. Don't take days off when you'll be at a rodeo, or Christmas, or family vacations, or for anything. Make your promise. Keep your promise.