Don't equate yourself to him. He isn't making you do anything. You aren't the one walking away like he did.
I've said several times you need to be a mentally healthy happy person with or without him. Stop allowing him to dictate your life to you, because that is what you are doing. You're his bitch. I know that's harsh, but its true.
What are YOUR terms, what do YOU want? If you let him come back without some kind of boundaries and standards he will keep sh!tting on you. Be a strong woman and set a good example for your girls, and that means getting a life with or without him.
Work on yourself Emily. Work on a career, go learn to do something new, take your kids to new places, join a book club and read good books, do the things *you* want to do. You don't have to make a decision right now about your marriage, let him show you how much he wants you back, otherwise you are just setting yourself to start this all over again.