I pray God will bring my husband back to his family

I pray God will bring my husband back to his family: My husband is 55 years old and has been in affair with a young girl who just turned 21 a few weeks ago. The affair started a year ago. He has tried to break it off a few times but says he loves her and it is complicated. He says he still loves me but doesn't know what to do. He move to a another state for work in February and I just found out he moved back a few weeks ago into an apartment with her. They now live close to her work and her family. (It is not close to our home.) He has completely turned his back on his two teenage boys, 14 and 15. We have two older children. They are currently out of the country working.
There has been no phone calls or text messages to the youger boys. Just an email. These boys know everything. I told them that their dad still loves them very much. He is just lost right now. And we need to pray for him and not to give up. I am in constant prayer about our broken marriage. I want my husband back. And I do believe God can make this happen. My heart is so broken and I am so sad. I feel like I have turned this over to God, but I just keep crying. I am on my knees daily.
I am filing for legal separation because of all the money he has spent on her. But I will not file for a divorce. I do not want a divorce and he says he doesn't either. I ask God to please touch his heart and forgive him. My husband has told me to pray for him and our relationship. I really believe with power and love from God this will happen. And he will come home to his family. I pray for the young girl too. I feel she is to young and lost to realize what she is doing.