I found out last week my boyfriend cheated on me while he is away at college. Before he left we sat down and had a very serious discussion about how we were going to stay monogamous no matter what. We also discussed how traumatic it would be for either of us if one cheated. Not even a month into school and he already cheated on me with the guy that lives down the hall from him! He tore down a year worth of trust in a matter of seconds. I cannot trust him at all. He gets angry when I'm skeptical about him, tells me I'm a black and white thinker, tells me him cheating on me wasnt avoidable. He just goes MIA for hours on Friday nights only, and it scares me because he cheated on me on a Friday. I'm scared this is a reoccurring thing even though he told me it was a fling and he has no contact with the guy. I'm so hurt that I cant trust him. I'm more affected by this than I like to admit, and he just goes on like nothing happened.