I am sorry to hear you had to find out that way, but I am glad you are at peace, take care of yourself, eat right, sleep, exercise.
Im sure in a legal stand point you have the upper hand if you had enough proof she commited adultery. Look into it.
Maybe the Vets can help as far as confronting her, I know I would want to myself more than anything but I probably know not to. I would kick her the heck out of my house though, not telling you to do that, just venting.. DO what YOU feel is right for you and your kids.