What the hell?

You date a guy for four years and your in love with the guy, but suddenly he stops talking to you for hours with in the day what the hell? I have no clue what to think anymore... maybe I should just go lesbian.. Just kidding.. But seriously I need help I have no clue what to do.. What if he is cheating on me? I do not think i would be able to handle that.. I'm tired of the tears that come at night (yes i know it sounds like a line from the song Lucky by Brittney Spears) Why are guys such ass holes?