@SusaNZ,
I am sorry for what is happening to you. You need to take care of yourself. If he left you and moved in with another woman then he has no respect for you. He does not have feelings for you. The friendly texts might be idiotic rather than intentionally cruel.. they are certainly thoughtless, but he might actually think that he is being nice. But he has destroyed any hope of you and him being together.
My advice
1) You should get a divorce for your own sake. He has broken the marriage and as sad as it is, it isn't coming back. A divorce protects you and will end up making things easier for your daughter.
2) The best thing for your daughter is to have a parenting agreement written and signed as soon as possible. This will make the arrangement clear and will make things much more stable for your daughter. In this long run this will limit the amount of drama that your daughter is exposed to.
3) There is a difference between civil and friendly. I can't imagine being friendly with him after what he did. You can be civil for the sake of your daughter. It would be reasonable for you to tell your husband that you don't want to talk to him other than to arrange times with your daughter... or you could insist that all communication is over email. I wouldn't want to talk to him after what he put you through. You can tell him you don't want his f*in texts.
4) You should see a divorce lawyer.