The fact that he's deleting his history isn't necessarily a red flag, especially if he does this often. For instance, one of my best friends likes to delete all of his phone histories and he does it regularly. I do this too from time to time if I think that I have too many text messages or call histories and I'd delete most things or everything just to clear away some of the "clutter" my phone accumulates after some time. But if he has only been doing this recently, then it does raise some eyebrows as to why.
The fact that he's getting angry could either mean that he has something to hide or he thinks that you are accusing him of something. Talk to him about this some other time and say that you aren't accusing him of anything and you're just curious. If he says that it's none of your business, don't go and assume the worse. He could be going through other problems that he just doesn't want to talk about. But I'd keep an eye on his behavior after this and hope that it doesn't continue to change. Change could be signal of something bad going on (not necessarily cheating though).
