I feel like I’m using this guy when I’m lonely..

So back in 2013, in May I dated this guy for about 5 months. Then in 2015 I dated the same guy in August until July 2016. Every time we start talking, I always want to stay friends but I know I still have undeniable feelings for him and he always says the sweetest things that makes me fall for him and date again usually when I feel like I’m alone. Then it’s always me who calls things off because I feel worried about getting hurt even though countless times he’s told me how much I mean to him and how his intentions aren’t to hurt me. He started talking to me again and I know I have feelings for him but I don’t want the same cycle to occur and I end up hurting him again. What should I do?