Cheater Cheater Pumpkin Eater

So...My boyfriend may or may not be cheating on me.  I was looking through his I-Pod and found an app for him to text on...I found texting to some girl, they were dirty texts and I didn't really know how to handle it...I just kinda tried to talk to him and when that didn't work I yelled, I didn't cry, I was angry and he had all of these excuses for why they are possibly on there...I don't know whether or not I can trust him...it's awful...I can't even trust my boyfriend...and I can't decide what I should do...I guess I just need to sleep on it.