Cheating...😬

I am 16 and I’m cheating on my boyfriend:( we’ve been together for 2 years and I know a lot of people will say if you loved the person you’re with you wouldn’t be thinking of messing around with someone else, but the thing is that I wasn’t in any relationships before this one and I feel like I’m being tied down and I haven’t had a chance to explore different kind of guys. ( not in a nasty way). This guy that I’m cheating with I’ve know him since third grade and I’ve always liked him but we’re not seeing each other we’ve just been flirting and talking on the phone. I don’t know if I’m making sense but I feel really guilt about this cheating thing and I just want it to stop. How do I get the guy that I’m cheating with to understand that I don’t want to talk to him anymore. This guilt is eating me up inside.