I don't think there is anything wrong with you snooping to verify if your H is having another affair. I think it becomes a problem when you know that he is and you still snoop . . . at that point it is only hurting you.
Do you even want to be married to a man that has such poor boundaries? He knows this relationship with this woman bothers you. If he cared about you, you are his wife and he should, he would stop it. Now.
He has had an affair and he has proven that he can't have women friends. I hope you don't tolerate this behavior much longer. You really need to protect yourself from this. He could be putting your heath at risk if he is having a PA with this woman.
I'm a man . . . But I can change . . . If I have to . . . I guess . . .