Exposure trick : I mentioned this before, but it may be worth experimenting.

Just make a fake call within earshot of your H. Talk about his affair and make it sound like you aer keeping someone up to date on his contaacting OW.

Find out if this PISSES him OFF.

If it does.. .you have a tool to pressure him into backing off of OW.

YOu may have to police them for a while... OIN had to do so for a few weeks, but I think he put that affair to rest... I see a similar line here...

In his case the OP wanted out and wants nothing to do with OM (at leat in claim).. and OIN's wife kept chasing OM.

Yours is teh same from what I can read (they may have us all fooled, I am confident enough to suggest we may be seeeing OIN's scenario here). His wife is as angry at HIM as your H is at YOU... and OW seems equially panicked as OM was when you called their home.

I think if you keep exposing, to fake friends or real ones each time you see ANY indication he's falling off the wagon you may be in the right direction.

I know it looks like you are policing him, but he's an addict and he's acting like a two-year-old... so, he has to be handled that way.