I lied to my bf and told him I was SA’ed and not raped

I’ve been feeling guilty about this for ages and it’s kinda driving me insane. I was raped in middle school by one of my boyfriend’s ex friends and I have only told him the half truth. I was on my first ever date with a guy at a county fair and he pulled me into a porter potty and raped me, It was in an extremely rural place so the porter potty’s were in the middle of a field with no one around. I told my boyfriend that her pulled me into it and tried to put his hands in my pants because I didn’t want him to see me as disgusting or treat me any differently. I feel so bad for lying to me and to be honest I’ve only told 2 people the truth and they were some of my very close online friends in Highschool. I love my boyfriend very much but I’m still scared if I tell him the truth he’ll see me differently but I’m also scared some how he will learn what truly happened to me because the guy supposedly likes to brag about it.