<human>: Can you provide a brief rundown of the text in within 3 sentences?

I was 15 and insecure, and for a year he put up with my jealous, unwarranted tendencies. It ended up with him keeping secrets from me such as his start of using marijuana which I felt was a big breach of trust, not that I have anything against MJ. I did everything I could to try to get him back including offering FWB, or indulging in weed and stealing to show we had common interests. 

Since then I've been with my current SO for 3 years and have changed. I was naive and immature then, and feel incredibly terrible for the way I treated him. He treated me as well as 15yo boy could but we didn't have the maturity to reason things out. Since then he has added me on FB (he deleted his old account, made a new one), and this topic has been lingering on my mind. My SO and I are doing great, so this has nothing to do with ulterior motives or my ex lingering in my thoughts. I just feel bad for being a bad person..is it worth it to msg him and apologize?
<bot>: 15YO couple, I was terrible to him and as a result, he was to me as well, but 4 years have passed and I want to apologize for the way I acted. Good idea? or no?