Help - How to handle catching your face in a lie?

So, I had a relationship in the past where my ex cheated. My current guy seemed to be getting very distant and showing the same signs. I ended up doing the one thing I told myself I wouldn't do again and looked at his phone. He was talking to other girls about wanting to see their breasts and stuff and how he needed to take care of his boners and so forth. I confronted him and we talked. Fast forward a month and I kept getting that feeling again. So I looked at his phone again and he now has Snapchat downloaded and it shows that he was talking to the same girls on there as recently as yesterday.

Forward to today, happened to look over at him as he closed apps on his phone as saw him closing Snapchat. Said, "didn't know you used Snapchat?" He said he downloaded it because of his niece but never uses it. Which I do know that she uses it.

So, that means I just caught him in a blatant lie.

How do I go about handling this? Apparently talking about it wasn't enough.