my boyfriend talks about kids a lot

he works at a school as a teacher aid. he always tellls me they are so cute and how he has his favorite little kids lol. I feel sad because i'm getting a gut feeling that i can't have any kids😔we always have unprotected sex and never fallen pregnant, he hasn't question yet but i'm scared to tell him theirs something wrong with me because i always have a gut instinct and he might be sad.