So glad you started a new post. I will tell you what worked for me when my sitch was similar to yours. It might not be what you need to do, but hopefully it will help you make a decision.
I too was so scared when I realized my H had reignited his A. He had swore it was over and was telling me he loved me. When I asked for reassurance he would tell me contact was minimal and then made me feel guilty for questioning him. But he was LYING AGAIN and telling me what I wanted to hear so he could have his cake and eat it too. When I found the text messages that he was seeing her again, it just about destroyed me. I came so close to having an emotional breakdown. I was so scared of everything - losing him, starting out own my own, what to say to the kids, and so much more. But I took the leap of faith and started detaching. At first it was hard, but then it became easier. I started to focus on me and dropped the obsession with H and the OW. I am still a work in progress but I feel an inner peace that I haven't felt in almost a year. I'm healing myself. I have decided that if we ever do try to reconcile our M, I need to do my internal healing first. So that is where I am.
Don't allow your H's actions (which you can't control) to bring you to the brink of a breakdown. It is so hard but you need to detach and focus on yourself and your daughter. It is difficult but it wasn't nearly as bad as I had feared. Take a step back. Start to heal yourself. And then take stock. Big decisions about the future of your M don't have to be made today. Take some time, heal yourself, and then re-evaluate. I hope that I have made some sense. I'm just worried about you right now - I know you are in a fragile place - I've been there! Please take care...
WCB
God grant me the serenity,
to accept the things I cannot change,
To change the things I can,
And the wisdom to know the difference.
- Reinhold Niebuhr
