It's not about what you had or did have...
It's not about who had it first.....
It's about who makes it happy. Sometimes we become selfish because of jealousy. Sometimes we need to consider that even though we as individuals are not happy, there are other people around us that are in high spirit of their situation.
You never had him to begin with. First impressions are everything.
Second ? . . . not so much.
You made him feel like a man, but that 'man' at that time was still a boy and still would be if he stayed with you.
Its over...
You moved on , he moved. He found somebody who made him the man he never was. She was now his queen. Him and her vindicated.
The green monster inside will not help you. The venom that comes out your mouth will bring you to your downfall.
She is in no competition with you. She doesn't have to be. It's she he loves not you. Rejection is what brings out the devil inside of us, many of us. You two are consanguineous.