Needing advice please!

My boyfriend and I have been together for a little over a year. There have been many instances that have caused me to believe that he hasn't been truthful with me, and it all bases around snapchat. (I have grown to hate that damn app..).

Anyway, one example and the biggest issue at hand that has caused me to second guess him was when he created a "secret" snapchat. We have had problems in the past about this app,and at the time he told me that he had deleted his previous account because he was tired of the arguing and me not being able to trust him. So weeks have passed at this point, and I get a gut feeling that is telling me to see if he created another snapchat. What do ya know, he did! I confronted him about it, he looked me right and the eyes and lied to me telling me "he didn't know how it got there" and "my ex is probably trying to start shit" which doesn't make sense at all. He eventually admitted to me, and told me the reason he did it was because he didn't want me to get upset and that "he was just looking out for me." Wha kind of bullshit is that!?! Anyway, ever since I have had trust issues with him and every now and then I will question him about things and he gets very upset with me when I do. He doesn't understand that once he looked me in the eyes after I questioned him over and over about the secret snapchat and lied to me, it broke my heart. He doesn't understand that the things he dies that do not add up or are not logical causes me to have disbelief. He doesn't understand AT ALL how he has hurt me. I've tried many times to get him to understand.

I am needing advice on how to get over this feeling that he is constantly doing things he shouldn't be doing? Or am I right to be feeling the way I am? Please help!!