My husband has KIK downloaded in his phone

I went on his phone because I sometimes like to look through pictures he’s taken on his phone from place we’ve been, etc. Well, he has a folder in there “kik” and in it he has 2 dick pics and selfies that he’s never sent to me. They were taken yesterday. What is the kik app used for? I don’t think I want to bring it up right now because I want to wait until I find more things first. We know the password to each other’s things. I tried to long into his kik account but it’s not the password that he uses for everything else. I’m leaving for navy boot camp soon, and now I don’t know if I can trust my husband nor want to stay married to him. If he had the desire to want to be unfaithful in anyway..I don’t know...now I feel like I don’t know who he is...together for almost 10 years, married for almost 2 this month..Should I be concerned? Are there profiles on it the app? Does it sound like he could be cheating?

UPDATE: I couldn’t contain myself so I confronted him. His excuse was “I was depressed, that’s why I did it” (he got fired yesterday based off his performance during probationary period) to me, this is NO excuse. He also said he deleted the app this morning (after I saw it) because he realized it was wrong and that he never talked to anyone on there. I don’t know what to do. I am hurt that he even had the desire to do wrong and my trust is working. Would a divorce be okay on my end over this? I am extremely hurt and will not be able to trust him when I leave for boot camp. Trust is broken and I am disgusted and now wonder what else he’s been doing behind my back.