First love break up

My ex and I have been together for 6 years, our relationship was rocky at first because we were long distance but in the end we made it. I’ve made mistakes in the past that I regret. But I thought we moved past them. He let his hurt go on for 3/4 years. We’ve been in and out of long distance to in person. He broke up with me last month because he felt like he just couldn’t forget, he said he forgives me but can’t forget. And that he loves me dearly but he’s not in love with me. And he doesn’t know if he’ll ever fall in love with me again. But always says only time can tell. He loved our relationship and won’t take it for granted it’s just he’s hurt. I owned up to my mistakes plenty of times and loved him and grown through our relationship and was the best girlfriend I could be. He said that I was an amazing girlfriend it’s just something he can’t forget. I do want us to get back together but I want it to be for us and not anyone else. How do I let go without letting go fully?