I betrayed my husband, and we are coming up on 2 yrs. of recovery this summer. If you want an inspiration success story read my update that I posted today:
My update I know exactly what you are experiencing. Understand, that chances are you DH DOES forgive you, but forgetting is another story. Don't ask him to forget, just allow it to take it's course. The best you can do is answer any and all of his questions, openly and honestly. As much as some of the answers may hurt, he will respect and admire the fact that you care enough to answer them. If you don't know the WHY of your affair, find it and share it with him. Chances are that he will never understand it fully as he didn't do it and probably wouldn't.
Know it's ok to not always have the answers, but at least let him know if you don't, don't just not say anything. That looks bad. Be understanding to his feelings and really truly listen. Don't defend or counter, acknowledge. You may not always agree, or you may feel he interpreted something differently then you had intended, but acknowledge that you see how he would/could feel that way, and then explain further how you see it. It's ok to see things differently, but as long as you both feel safe to discuss that with eachother, that's the important part.
Reassure him each and every time he needs it. Do little things to show him you love him - plan a candle lit dinner, dance under the stars to your favorite song (wear a dress for this). Reexplore the intimacy in your marriage and do it together.
The road ahead will be long and bumpy, but remember that 2 steps forward and 1 back is still progress. Be patient and know that the end result is well worth it. It's a lot of work, but I promise you it does get better.
My best to you. You are on the right track here, and the people here are a wonderful source of support and help. Hang in there. Take care, and good luck rebuilding your marriage.