Is it normal to still have these feelings?

So, for about 9 months now, ive been OFFICIALLY dating this guy. We met last year and we started to like each other, then eventually blossomed into love. He always told me how much he loved me and I always believed him; we snuggled all the time when we were both in school. It was like we were dating, just without the title. Anyway, I have a friend (let's call her Ally and the guy Robert). One day, after school, Robert came up to me and hugged me and started telling me over and over again that he loved me, which really concerned me cause i can tell something was wrong. Later that night, he called me and told me that he was starting to like Ally. This broke my heart, but pretended to be OK. Then, when we were at the library hanging out with our friends, Robert and Ally would snuggle. Right in front of me. And it hurt. A lot. And i didnt like it that i hurt cause i had no right to, considering we werent "dating". there were times when he would stop snuggling with her then snuggle with me, which didnt make me feel any better. All my friends wanted to kill or hated him for this, cause everyone knew Robert was hurting me, except himself. Robert wasnt being greedy, okay? He is not a bad person for this. He just didnt know who he wanted to be with. He was confused on his feelings. Later on, Ally found a new guy, which helped Robert make his decision to be with me, and then we made it official about a month later. About a few weeks into our relationship, Ally and I were talking and she warned me about Robert and to keep my guard up cause before we started dating, Robert and her were so close to having sex. This broke my heart. What did i not have that Ally had? It hurt. (she told me this on my birthday.... it wasnt a very happy birthday...) I called Robert that day asking him about it. He admitted to it, and said he was really sorry. He also admitted that even though he never had sex with her, he did do sexual things with her. Which hurts so much. Everything was resolved, but to this day, 9 months later I still hurt from it. To the point of tears. I still cry at night cause of it. Am i overeacting? Am i being childish? Am i being immature, or do i have the right to still feel this way?