I know exactly what you are saying about wanting your husband to be with you because he really wants to be and not because he has "lost" OW. But situations, feelings and relationships can change dramatically. That's where changing yourself comes in. You need to be the woman he originally fell in love with and married. And again, do that for you, not for him.
Until things cool down with the affair, your husband probably won't be able to appreciate what he has lost. And unfortunately, the affair may take a lot of time. According to books on this, the average is about 6 months... but, of course, some are shorter and others longer.
You sound like a very nice person. Do NOT let that niceness keep you from getting exactly what you are entitled to (and anything extra!!! Your kids will need it!!!! It's for THEM).
Do not argue or discuss any divorce details with your husband. If he says anything about this tell him to write down what he wants and either leave it at the house or send it in the mail. Do not agree to anything and change the subject when he wants to bring it up or tell him to just write it down. Tell him you need it in writing and time to go over it and think about it. If you need to discuss divorce details with anyone ONLY talk with a lawyer. Also, drag your heels on everything. Be BUSY BUSY BUSY!!!! (Running, working out, weight training, etc...).
There is no arriving, ever. It is all a continual becoming.