I made the best decision?

Before asking your opinion I'll start by telling my story.
All started about one year ago when I met him in the oddest way. At that time I had a best friend named Raquel and told me that there was a guy who she liked a lot and if I could add him to Facebook, so I accept and add him. A week later the guy had sent me a message. I replied him because I thought it would be the last time he send me a message, so I decided not to tell my friend. My surprise was that he started to speak to me a lot. And every day that passed, I was aware that we had many things in common. Soon we began to go out the three of us (my best friend, he and I), and I began to consider him like my brother, and so do him. But over time without realizing it, we couldn't spend a day without talking because we missed, we were going anywhere together, we began to treat us as a couple and people began to ask us if we were dating; and obviously our answer was no, we are only friends. But eventually we begin to believe what all the people told us and unwittingly, our feelings began to change. I talked with my best friends and told her that without wanting it, my feelings toward him had changed, and obviously she get mad. Two weeks later I decided to talk to him; and I said I felt guilty because my best friend had confided in me and I had taken the attention of the guy she liked, and because of that I thought that it was not the best idea to be together, at least until things calmed down. He at first didn't agree, but then he agreed that I was right and that it was not the moment to be together. When things get calmed down, we talked again and we started a relationship. The first months all went well, it was an incredible relationship. We never had a reason why to fight. But one summer everything changed, I went to Spain with his friends for one month; at first we talked almost every day, but suddenly we stopped talking. And when I return things obviously changed a lot. It was not the same, we fight almost every day for things that are not important. And gradually we stop having things in common, his life began to revolve around alcohol and I pass to a second term. I was very sad, and I can't understand at what time everything had changed, and when I had ceased to be important in his life. A few days later, I decided to talk to him and said it was the best we finished, because now we had no things in common and because things were not working. Being honest at first it took me a lot of work to get ahead, I didn't want to go to the place where I could meet him. But eventually I understood that I had made the best decision, and although at that moment it hurt me a lot, now I was a totally different person because of him.
Now that you know my story, do you think I made the best decision?