super quiet after sex??

after my boyfriend cums, he gets really quiet and like goes on his phone. he’s the only guy i’ve been with and we’ve only had sex a few times but is this normal? because i’ve heard about people cuddling after sex but this doesn’t happen. is this likely to just be a him thing or is it something i’ve done?? could he be embarrassed because he always cums really quickly and i don’t cum at all??