Found out husband is bi-ual and having in his car?

I just found out that my husband has been having bi-ual affairs and is renting rooms for his "liasons". He has no idea that I know anything about this. He has ual trysts with both males and females. I check his text messages and emails on his phone and that's how i discovered it. He would flip if he knew that I was snooping and part of me wants to call one of the females that he has been trying to see just to tell her to stay away from my husband!! He lies to me about "going to the gym" when he's actually renting a room or wanting to meet someone for . How can I approach him about this without letting him know that I've been snooping around? I don't understand this bi-uality all of a sudden and the fact that he places these adds on craigslist stating that he is willing to travel "right now" if he can find a willing partner to have and other lewd acts in his car. How do I approach this when I'm not supposed to know? And, the kids are getting a bit suspicious. What do I do? PLEASE ADVISE ASAP!!! Thanks