Irritated🙄

Teri
Hello ladies! Well this is my first post so here it goes I'll just jump right in there lol. 
I'm not sure if this happens to anybody else, but I can't cum during sex😭 it's only happened to me twice in my life. Now don't get me wrong, when I have sex it feels good but it just seems like when I'm actually having sex I can't cum. When I masturbate I have no problem setting it off in no time lol! But I'm not sure if it's an intimacy thing or a physical thing. Does this happen to anybody else?🙄
xoxo,
Teri💋