Just to explain what we are doing here in a bit more detail.

You cannot END someone else's affair.

What you CAN do is INFLUENCE the PACE to which it progresses.

All affairs END eventually... some end in a few weeks, some take ten or more years...

The thing is... the abandoned spouse has a strong influence on the pace of the affair they are being exposed to.

Their choices and actions can speed it up, or slow it down...

When you EXPOSE, you speed it up
When you act nice and needy, you slow it down
When you DETACH, you speed it up
When you fight with him, you slow it down
etc

This is a smilar question to Michel's is what I am about to say or do giong to bring my spouse closer to me or further away...

The question here is

Is what I am about to do going to speed the demise of the affair UP, or is it going to slow it DOWN?

Isolating yourself into a safety zone WILL speed the demise UP... you are forcing her to deal with him FULL TIME... and he won't have you to RANT with ... so.. you guessed it.. he will antagonize HER instead.. he will BLAME her for your shutting him OUT... All of that ugly business you dont' have to expose yourself to... so you get time to rest and heal.

When you shut yourself off from him.. But him knowing you WANT him back when his affair is over.... This puts a LOT of pressure on him to DEAL... She's got a world of problems on her end to deal with too so... That's just icing...

He's trying to pull you IN... when you zone OUT then its better for YOU and worse for HER... Let those two bicker and complain at each other... don't let him bring you in as a third party to that nonsense...