Sure there are do-overs! No one is the perfect parent or says the perfect thing all the time. Don't put so much pressure on yourself, eh?
Remind your daughter that we can still love daddy, but we can't live with his hitting people any more. That's not okay when someone hits you.
As for your daughter's anger, you can tell her that you will always be there for her, and that you're not going to leave her. When she's angry you can talk to her, give her time-outs, talk afterwards about it (what made her angry, what else could she have done rather than act out) and remind her that it's okay to be angry but not okay to (hit, kick, pinch, scream, whatever she's doing). This is a time when you can encourage and teach her to talk about her needs and her opinions, and be there to listen and consider them, and negotiate her needs with her. If she's nervous you might leave because she hits, you can tell her this won't happen, that she is still a child and is still learning about anger, and that takes awhile and that you will help her learn not to hit.
And sure there are do-overs. You can say "Remember when I told you that [blah blah blah blah]? Well I've been thinking more about that, and now I think that.........etc." Include her in the discussion, saying things like "how would you like me to act when I'm angry at you?" and "How would you like to handle it when you're angry at me?" and talk about behaviours, how hard it is sometimes when you're going through big changes, and that you love her, daddy loves her, and that you and she will get through this and be okay. Ask her what she thinks of all this. She needs to know that her opinion is important to you and that you want to know what she's feeling and thinking, and that the two of you can discuss things.
Don't be too down on yourself.....you're doing great and handling a huge situation right now, maybe the toughest situation of your life. One day at a time, and don't forget to breathe!
Rivergirl