If he forgot what you meant to him, then it means he took you for granted. It means that he set you aside, set your needs and your worth aside in order to prioritize himself and only himself. At one point in your relationship, he got too comfortable with the idea of you putting in all the effort. Maybe he figured it was easier that way, or maybe he lost sight of what and who is most important, or should be, at least. That doesn’t mean that he doesn’t or won’t realize this. Who knows, maybe he won’t but that fact doesn’t really matter. What matters is that you learn to acquire the strength to stop fighting for him. Don’t ask him to change. He won’t.
If he forgot what you meant to him, it means that he gave up and let you go. And now, you’re stuck feeling betrayed. This was not how it was supposed to turn out. He was supposed to be there for you, always. He was supposed to love you, always. And if that changed on his end, it was something he should’ve vocalized. Instead, he let himself forget about the connection you two shared, he let himself forget why it is he fell in love with you in the first place. This is a loss, one that was perpetuated by his inability to give you back what it is you gave him.
If he forgot what you meant to him, it’s okay to think about and hope that, some day, he’ll realize what he lost. This is a broken promise, and you’re burdened to carry that with you for as long as it takes to move on. You’re the one who hoped he would stay, who wanted him to stay, but he didn’t. You were forced to let go because a real, intimate relationship isn’t one sided, and neither is love. It might take longer than you hope, but you have to know that, at some point, he’s going to miss you. He’s going to think about you. Does that mean that he’ll realize how amazing you are and want you back? I don’t know, but I’ll be honest with you, you shouldn’t hope for that.
If he forgot what you meant to him, you should know that it’s not your fault. You shouldn’t have to remind someone to love you. It’s on him. You did everything you could to make this work, and he, unfortunately, didn’t see that. And if he did, he clearly didn’t care. But in truth, it’s better to stay away from assigning blame. He made his decision and you need to accept that. What you feel now and what you want now doesn’t matter. Just remember that it doesn’t say anything negative about you. I know a lot of girls will think it was something they did, that maybe they weren’t worthy of that love back, but all of that isn’t true. It’s not your fault.
If he forgot what you meant to him, and I mean, if he abandoned his promise to be with and love you, then you’re better off without him. That’s the truth. Granted, it might be hard to believe and maybe even harder to face, but the reality of the situation is that you don’t need someone in your life that needs to be reminded of why they love you. That’s something that shouldn’t fade but he allowed it to. You and I both know that you deserve someone who will put you first, who will reciprocate those feelings, and who will fight to keep you around.