The only way to "fix" this situation is by rolling the dice - let him go. Most affairs don't last 6 months beyond the spouse discovering the truth. Once he has an opportunity to spend all the time he wants with the OW, he may find he still thinks she's perfect and you lose. BUT, the fog may clear and he may start to see her for exactly what she is - a whore that he could never trust because she's willing to have an affair with a married man. And her perfection will start to wane as soon as normal lifes problems enter into their relationship. After all, an affair is all about only seeing/spending time/talking about things when you're both at your best. As soon as bills, broken cars, sick kids, etc. enter in, the fantasy is over.
I agree with Jana. If your H is so convinced that OW is perfect, nothing you do or so is going to get his attention. It's going to be seen as pursuit. If you let him go, they will experience the real world together, not this fantasy they've been living in. It's a tough road. But one of the books I read detailed this same scenario. (Book: Surviving an Affair by Harley and Chalmers)
OW may think she's winning (what a b!tch) but what you do in the meantime is critical. You GAL GAL GAL! You're upbeat, happy and friendly every time you see him. You look great. You act mysterious. Have fun with the kids. Be his friend. Let him see what he will be missing. Then, when the fantasy between H and OW starts to fall apart, where do you think he's going to go?
Again, not an easy road for you, but if you're interested, get the book. And, if you want to be the winner, you're going to have to buckle down and fight, and take the low blows with the high blows.
