I cheated on my boyfriend

I admit it I'm a cheater, so PLEASE no rude comments. Currently, have a boyfriend we have been together for a year now. My ex-boyfriend was my high school sweetheart after we graduated he broke up with me and moved to a different city. I lost contact with him. I went off to college and he didn't. I met my current boyfriend at the community college I go to and he is just completely amazing with me I love the way he treats me and spoils me. Out of the blue my ex boyfriend added me on Facebook 3months ago I made a huge mistake and hooked up with him I've been seeing him ever since, but I can't do it anymore I want to come clean with my boyfriend I tell him everything tell him how sorry I am ? I regret it completely I already told my ex boyfriend that the cheating has  to stop and it has. I have no idea how to tell my boyfriend all this. Has anyone else been in this horrible situation?