I feel like my boyfriend is cheating on me...

Okay so my boyfriend and I have been together for 2 years and 2 months... Lately we have been at each others necks! And I found out that he had a snapchat(we both agree ded we wouldn't have one because we didn't want anything to get in the way of us) and so he snapchatted a girl I don't care for and he knows that I don't like her! He said he needed someone to talk to about us but I know that's total BS!!!😒 ever since that, I don't trust him and every time I'm around his phone he gets all weirded out and I found out he's using he's iPad to message people with no names!!!??? Like what is this mess?? I'm so conflicted ...