He couldn’t commit to marriage and kids

My partner and I broke up last week. I initiated the conversation with the hope that he would realise he is about to lose me and get his shit together. Instead, he gave up. He let me go. Even though I really didn’t want to go. I have been with him for three years. He was my first boyfriend. I had so much hopes for us. I knew he wasn’t eager about marriage and kids in general but I gave him time and space. We initially broke up a few times in the first year of dating. The last time he wrote me letters promising he has changed and sees a future with me. Two years went by and slowly he changed back to his old self. It hurts so much but I am so disappointed that he gave up. I know I should be grateful that he finally let me go. However, I am still thinking whether it was me. Whether I should have tried harder. Whether I could have done something to change his mind. But he let me go. Damn him.