I'll give you some advice a friend gave me. Your husband is lying to you because he is ashamed. Your husband is going through alot. Everyday issues plus infertility, an aborted baby, an OW. He is having a rough a time as you. If you want him to come back listen and practice the DB techniques. Love him unconditionally, don't argue, agree with his feelings, get on with your life and be happy. Don't give up hope. He says he still loves you, which is more than most DB'ers have. He won't ever forgive himself for this act, so you have to accept that, but is that ground for a divorce?
You have a lot to think about. Do you want him back? Do you want to go on with your life?