Confused about my Girlfriend/and friends

Hello, everybody! So, I'm not quite sure where to start exactly... I'm a young guy who has recently gotten out of a 2 year relationship with a girl who I truly loved. She was my best friend and most trusted companion. Everyone including all of our friends used to say we were perfect together. A little after 2 years, things just became... A little monotonous. Neither one of us had done anything to the other, we just felt that we needed a break. So we broke up. About a month after this, I found out that she had begun talking to one of my close friends and the two had a bit of a small "fling." This of course made all of my friends very angry at her and eager to help me move on (although I was still hurting pretty bad.) All in all, things did not work out with her and him but they had both apologized to me multiple times since then. Anyway, my friends set me up on multiple dates, and before I knew it, within a few months I was in a relationship with a different girl. I thought, "Wow I got over *insert ex's name* pretty well!" However, things did not work out with the new girl and that relationship crashed and burned. Around, Thanksgiving of this year my ex texts me after learning I was in the hospital (long story.) She was making sure I was ok. At this point neither of us had spoken in a while. We got to talking And ultimately we both apologized for ignoring each other and how distant we had gotten. Things were looking good! We became best friends again almost immediately, which of course all my friends noticed and told me to be careful. "I will be," I quickly assured them. And so things went on for a few weeks until she told me that she may still have feelings for me. I admitted that things were going very well between us. We began to talk about what it would be like if we got back together. We did not end on bad terms, but other People made the post break up a very messy ordeal. I want to be with her, but all of my friends are telling me not to do it. We've been secretly "talking/flirting" for almost 3 months now. It is clear that these feelings are real, but how do I tell my friends about it? What will I do if they all hate me because of how much I used to bag on her to them. Should I truly be with this girl? We may even both love each other again. I don't know what to do. Please I need some advice!

Thanks you for responding, Yes I know it was definitely wrong to say those things about her. Like I said, my particular group of friends were eager to help me move on quickly, and I played the part as best as I could at the time. It was a mistake. Thank you for your advice, I'm sure things will work out