Communicate. Talk to him and if he doesn't wanna listen or doesn't talk, and you don't want to put up w it then I say you end it. Try totalk and see what's going on, if you are suspicious it bc there is something going on. Talk it out, but if you are getting hurt abd he doesn't talk I say end it
Remember the saying "never make someone a priority when they make you an option". Listen to your gut girl...it's usually never wrong. He may not be cheating, but it doesn't sound like he is a very attentive boyfriend. Always remember you deserve the world and if he isn't going to give it to you, there is someone out there who will. Don't waste you time on a guy like that.
Tell him you lost your phone and you need to call someone really quick. Ask for his phone to call someone secretly in a room or something and that you will tell him what it's about when the time comes(never)if he lets you borrow, all is fine. If he doesn't, ditching time!!