Should I tell his wife? not sure what to do?

ok..so I know you're going to judge me and I cannot explain how complicated this whole situation is...but the jist of it is I am a mistress with a married man. This has been going on for 5 months...his wife found out about us about almost 3 months ago...and he moved out. He is not living with her and I know this for a fact. She does not know that we still talk and see each other...in fact she thinks they are working on their marriage...not sure how she thinks they are doing that without living in the same house but thats besides the point. He has gone so far as to buying his own cell phone plan and only I know the number so that we can keep talking as much as we want because she was checking their phone bill for my number and stuff. We talk every night on the phone for at least an hour and a half...text all day long...see each other quit frequently...he lives 3 hours away so its not that often but within the past 3 weeks weve seen each other at least 6 times. He tells me he loves me wants to be with me...he's going to leave her...I gave him until sunday to do it else I'm done and were over. Tonight we were talking and he told me he knows we need to be together and all this bull **** but that he can't bring himself to end it with her by sunday...he doesn't know why but he just can't...well I mean I'm not stupid the reason he cant is because he's a cheating *** hole and wants his cake and eat it too. Anyways..I told him I was done..he wont stop calling me, texting me, e-mailing me, begging me to talk to him. I think she deserves to know...and if i were in her situation I would want to know. And actually when she found out the first time she called me and we talked on the phone for over and hour and a half...I know it sounds messed up and it is...but what would you do? SHould I tell her or not? I think she deserves to know the truth..and I know I would want to know..but maybe I am crazy..well i already know i'm crazy for doing any of this in the first place..