Looking For advice

Me and my boyfriend have been together for a while now . But over the past past month i have noticed that all he jokes about is sex , or asking to have sex or just whipps his dick out and is like let's do this . But whenever i say no he gets all pissy and mad and ignores me . How do i talk to him about me not wanting to have sex everyday or not wanting to do sexual stuff in general with him whenever we're together?