I'm so sorry to hear what you guys are going through but try to look at this as an opportunity to show your daughter how to overcome obstacles. Life is full of unpleasant things. In these situations, you have two choices: 1) Look back at think about how things could have gone, how they went and how they should have been or 2) You can look forward by learning more about what happened and focusing on how you can make it right.
You are your daughter's role model. She is looking to you and counting on you to make this right. She is watching on you handle this and you need to find it in you to show her *how* it's done. We,as Moms, don't always make the best decisions but we make the best decisions at the time. Hindsight is what it is and she needs you to show her how to come out on top.
In terms of dating, I would make efforts of going to places where you like to do things- churches, book clubs, coffee shops, parks, etc. You may even talk with some friends about trying to meet more people. Make yourself available. Open up to the possibilities and it will happen.
As for your daughter. You are smart not to involve your daughter into this dating stage. Try to wait until things are really serious. Have a conversation with her about what type of "guy" she thinks would be good for Mommie. Start talking with her about healthy relationships and involve her in the idea of finding a nice guy. Talk with her about unhealthy relationships too and talk with her about what "unhealthy" is. It is so critical for young girls, especially that have been exposed to such a bad situation, to talk wtih them about the difference so that they know how to handle situations going forward and so they don't put themselves in a similiar position.
Another suggestion is that you might consider counseling for both of you to help put the past in the past. I feel bad for both of you but you sound like you have your head on straight and will be able to get both of you past this time.
Best wishes to you both.
N.