I DONT CUM DURING SEX!!!😤😤

Debbie
Hey ladies, 
So I have a quick question, my boyfriend and I have sex regularly and we've been together for a year. 
I enjoy clitoral stimulation and thats usually my external g-spot. When he rubs on my clit (or I play with myself) during sex, I'm usually able to cum. But that gets tiring and I want to learn how I can get internal vagina stimulation and also cum/have orgasm just from having intercourse - without the need of rubbing on my clit.
Thank you xx