Also gardengirl, i WOULD definitely expose to his newfound daughter.
She may put some pressure on her mother... the more pressure and embarassment you can put her through on her end the quicker you will put this affair to an END.
You may not want your husband back, but that's no reason to enable your husband to cheat on you.
Phil McGraw always says you have a right to end your marriage, but you have to earn your way out, you can't go sneaking out the back door lying and cheating... that is NOT the way to end a marriage... it indignifies many years of commitment and your marriage is worth ending it with the respect it deserves.