5 year double life and counting... :-(

Hi,
I am in such a strange and earth-shattering predicament. My husband of 12 years, college sweetheart, and father of our 4 children has been having a double life with a woman he works with for 5 years now and counting. The woman has known about him being married and even said she was jealous of our marriage. Well she has also said she doesn't care about him being married to me and has no intention of not being with my husband. My husband said he cares about her but mainly he is being driven by the fact that discontinuing his relationship with her will affect his business substantially hence the reason he will not stop seeing her. He said it's hard for them not to be intimate because it has been the nature of their relationship for going on 6 years now but he is in love with me. He said if it wasn't for the fact that he wants to be able to provide for me and the kids plus reach his financial goals...he would have left her alone a long time ago. I am in such a hurtful place because he pretty much has asked me on several occasions if I could just accept her knowing that his heart is truly with me. Of course based on righteousness, self-respect, and my children I said an emphatic "No" but it hurts deeply because I know he has feeling for her and will not just choose me and the kids over money, image, status, etc. I told him we don't need the money, etc but it's not only for us because he is being led by the spirit of mammon. He is not willing to stand for righteousness and it's tough because I didn't marry a Christian man so how can I expect him too? I guess I at least expect him to have a conscience. I'm just so hurt. We've been going through this back and forth for a year now. I filed for legal separation finally but with everything going on I know I still love him and he says he loves me with all of his heart. Of course I don't believe him when he can literally see how his actions destroyed me and continued them but that's what he says. I tried not being intimate with him for a bit...I tried stonewalling...I kicked him out of the house...and now I filed for legal separation and he still will not stop sleeping with her or seeing her. He believes his end justifies the means and she makes it that much harder for him to stop because even when he tried to get rid of her last year...she made it extremely difficult by messing with his business, threatening suicide, and popping up on him wherever he went. I feel like there is no hope. He always says he can't live without me and that I complete him but if that were true than he wouldn't need her. I don't know what to do honestly. I've been listening to the videos and he agreed to do the first steps bootcamp but hasn't started yet. I hate divorce but I feel like it may be necessary in my situation even with my heart still connected to him.