Hubby cheated... Now he wants to act like it never happened?

I have been married for 17 years.Happily for 15. In 2007 my husband had an affair with a 25 year old that he met while in school. It started in Feb 07 and ended in August of 07. I have tried to forgive and to forget but I cant. While enduring pain and heart ache from the whole affair thing, I started talking to a gentleman on CL(Platonic section). We started out talking about how we have both been hurt by cheating spouses... and eventually one thing has lead to another. We have acquired feelings for one another and he is a wonderful caring man. He treats me so wonderful, and I have never been happier. we have since moved in with one another and things are going great.. ... Here is where I am having trouble. My husband of 17 years is acting like I have not even left... he is trying to kiss me, and tell me how beautiful I am, and he has even helped me move in with this other man.. ( I know.. that is weird) But he says that it will give me time and space to realize that we are meant for each other. I am not a mean person, and I am having trouble telling him that I want to move on with this other man. I realize that he was mean and hurtful while having the affair on me, so I should be the same to him, but I am not like that.. I do still love my husband, but not like I did 15 years ago. I only love him for the good times and the children.. But I am ready to move on. Should I just file for divorce and spring it on him, or should I tell him that I am going to get started on filing. I just want this to be over, so I can move on with my new life and my new love..