IIN to be nosy in a relationship sometimes? Literally just sometimes.

That's not normal of him darling. If someone gets that defensive over just being nicely asked 'what's making you smile on your phone' is suspicious to me. If he had nothing to hide in the first place then he wouldn't be so defensive that is a dead give away! This isn't really similar but I once had a close friend who said 'don't be nosy' when I was looking to see who had come up the driveway at her house. I found that rather random and mean, I suppose I am just saying this as some people are very weird and random. Though in your case I feel he is untrustworthy