[22M] and [21F] in a relationship for a year an a half. He doesn’t want kids anymore after telling me he did.

So me and my bf have been dating for a little bit over a year. we have had multiple conversations about having children and we both agreed we wanted them. i have always been transparent about how much having kids meant to me. out of the blue today my bf said that he would not be sure if he even wanted to have kids until he was in his 30s. i don’t want to break up because he means so much to me but i don’t see either one of us changing our view on it. i need advic