Husband left when I was 12 weeks pregnant. Advice?

Keeping this a little vague because I have friends and family on this app. So to make a very long story short: I have a toddler and am due to have my second baby in September, I had been happily married and both pregnancies were planned. I'm in my early 20s and my now ex is in his late 20s. one month after finding out we were having another baby, he cheated on me, asked for a divorce and is now only seeing his child once a week or once a fortnight. Obviously there is a lot more to the story but basically just want to make a point of saying how cruel he was to me and that I am still in shock months later at what my life has become. I love my child though and am starting to see how this is an opportunity to build the life I want. What I would like help with is advice from others who separated during pregnancy. I've already decided I don't want him in the delivery room, I've told him this and he understands why. But having a baby is so life changing anyway, let alone bringing a baby into the world when you are going through a separation from 3 months into the pregnancy. Does anyone have any advice for things they wish they did or things they're glad they did in this situation?