I am confusion

Hi! I (17/F) am in my second ever relationship (19/M). He’s awesome and we’ve known each other and dated on and off for the past two years. I could honestly see myself marrying him, but I don’t think he feels the same. We’ll go through days/weeks where we talk all day and constantly hang out (when not in a pandemic) and he tells me how much he loves me and wants to stay with me forever and all this. But he’ll stop out of no where and won’t even carry a conversation. It hurts a lot, and makes me feel like none of our relationship matters. I’ve tried to ask him about it but he never gives me an answer. I’ll be graduating this coming year and I won’t be staying in state for college. Should I push and fight for this relationship or just let it die out? He’s honestly amazing, he just forgets me