He gets upset with me

So recently me and my boyfriend everytime were together he constantly wants a blow job like don’t get me wrong i’d love to give my mans pleasure but damn all the time can be tiring and sometimes i just don’t feel like it and he’s always asking. Now everytime i say no he always questions me like why not blah blah blah and then acts like i owe him something and then gets in a bad mood like seriously that’s crazy right ?