Okay - so he's not sounding QUITE so much like Scott Peterson now - unless, of course, he's trying to butter you up to get you to go "fishing" with him. Just don't get in any boats, okay?
Expect him to swing back and forth - standard MO is to swing close, then swing back towards OW, then swing back.
If you are considering taking him back, make sure he knows he needs to get some counseling for himself to figure out why he went off the deep end like this.