I really, really need this answered! Please help!

There were rumors a while ago that my boyfriend has cheated on me. He denied it and ever since then, I just feel our relationship is slowly going downhill because I don't know whether to trust him or not. I need to know if the rumors were true or if my boyfriend really has been faithful to me. Please help! If I know the truth, I will know if I can truly trust him and move forward in a positive direction. Thank you.