Trees, I've been reading all along, you've been so strong.
I myself am 7 years strong with someone who betrayed me early in our relationship. It's taken a lot of time and work, but I respect him and trust him after it all. My OH took full responsibility, came clean, etc.
Don't slip into the old comfortable habit now. Make the big decisions about your relationship later, when the hormones aren't so fresh and the baby isn't just here (congrats by the way!). If your WH spends some time thinking about what he's lost, it will only improve his gratitude for what he does have should you guys reconcile down the line. You need this time for you, otherwise you could jump back into it too soon to know if it's just out of comfort/fear of being alone etc, vs taking the time to be individuals and reflect on what you each need from each other for a relationship.
Separating (permanently or for the time being) does not mean you aren't giving your children the best. If you and WH are both loving involved parents and have as healthy a relationship (whether that's just coparenting or an actual relationship), you are doing the best you can for the children. You've been remarkably strong, and in my experience, the folks who take a step back from a relationship with betrayal seem to have a better chance at recovery than those who just carry on right away. Wishing you the best!