ADVICE NEEDED: She Is 19 Year Old 200 Level Student Who Wants To Stop Having S£X

I am 19, 200 Level and I have been dating a guy in my school for about a year. We are really in love and we hope to get married in five years time. We have been having sex at least twice a week since we started dating.  
Although we use contraceptives I am really scared of getting pregnant especially because my Mom is a pastor. 

I want to stop having sex, at least for now but each time I tell my boyfriend, he says I don't love him. I don't want to loose him.