I keep hurting people

I was with my ex for more than 4 years, then I met this other guy who was the exact opposite of my boyfriend. My boyfriend was a good person, but this other guy could make me laugh, he was very smart, popular, active and brave and he really seemed to like me. So I left my boyfriend for him because I thought that it might be the chance to change my life, to reach for new goals, ect. I thought that me and the new guy were very similar and had same interests. I dated the new guy for 2 months, but then I started to miss my ex every day more and more, i started to think about how comfortable we were, how sweet and reliable he was and maybe after all our relationship weren't so bad. I also started to notice some personality traits which I didn't like in the new guy. Sometimes I felt insecure around him because he was always smarter, funnier than me, had many female friends and I thought that eventually he would realize that I'm not good enough and leave me. I started to think that maybe I made a mistake by leaving my ex. So one day I texted my ex, left the other guy and got back together with my ex. However I don't feel any better. I don't feel happier now that we're back together. I feel like things are exactly the same like they were before we broke up.. And of course now I miss the other guy. I feel stupid and just don't know what to do. I keep hurting people around me and I still don't know what I want from life or my partner. I don't want to hurt my boyfriend again and I know that he would never forgive me if I did something like that again, but I'm not sure if I will be happy with him. So if anyone has any advice, I'm open for suggestions..